home · Measurements · A simple electrical circuit for an alarm lamp burnout. Electrical circuits of process control and signaling. For the circuit "Network voltage level indicator"

A simple electrical circuit for an alarm lamp burnout. Electrical circuits of process control and signaling. For the circuit "Network voltage level indicator"

General diagram of the electrical equipment of the car


Control devices, sound signals, electric motors, radio receivers and other devices that do not have individual (built-in) protection are protected by fuses.

Rice. 1. Schematic diagram electrical equipment of the ZIL -130 car: 1 - relay regulator, 2 - generator, 3 - ammeter, 4 - battery, 5 - starter relay, 6 - ST130-A1 starter, 7 - ignition switch, 8 - additional resistance, 9 - coil ignition switch, 10 - transistor switch, 11 - distributor, 12 - spark plug, 13 - bimetallic fuse block, 14 - heater motor switch, 15 - heater motor resistance, 16 - heater motor, 17 - turn signal breaker relay, 18 - flashlight warning lamp, 19 - indicator lamp for emergency water overheating, 20 - temperature sensor, 21 - fuel level indicator, 22 - fuel level indicator sensor, 23 - water temperature indicator, 24 - water temperature indicator sensor, 25 - indicator lamp for emergency drop oil pressure, 26 - pressure gauge contact, 27 - turn signal switch, 28 - brake light switch, 29, 30 - rear lights, 31 - sidelight, 32 - headlight, 33 - light switch, 34 - engine compartment light, 35 - courtesy light switch , 36 - lamp holder, 37 - foot light switch, 38 - socket for high beam headlight warning lamp, 39 - socket for instrument lighting lamps, 40 - bimetallic fuse, 41 - plug socket, 42 - sound signal, 43 - horn button (included in steering column kit), 44 - plug socket, 45 - turn signal repeater lamp

The ignition and starting circuits are not protected from short circuits so as not to reduce their operational reliability.

Thermal fuses are divided into multiple and single action fuses. When there is an overload or short circuit in the circuit, the relay fuse contact pulsates, turning the circuit on and off. The single-action fuse contacts open in these cases. Turn on the fuse (close the contacts) by pressing the button.

Fuse links are replaced after eliminating the causes that caused them. short circuit. When replacing a fuse-link, use only wire of the appropriate cross-section. For example, with a maximum fuse current of 10 A, the tinned copper wire of the fuse link must have a diameter of 0.26 mm (for 15 A, respectively, 0.37 mm). It is strictly forbidden to use thicker wire (“bugs”) or factory fuses designed for a higher rated current.

To prevent electrical wiring faults, it is recommended:
— periodically clean wires, screw and plug terminals from dirt and moisture;
— pay special attention to the condition of screw and plug connections, avoiding corrosion, oxidation and weakening of connections. To prevent oxidation of the contact surfaces of the joints, litol lubricant, etc. is used;
— regularly check the voltage drop in sections of circuits and contact connections of the main consumers of electricity.

Most of the faults in electrical equipment of automobiles occur due to untimely and poor-quality maintenance.

The main malfunctions in the on-board network are:
— break in the chain of sources and consumers electrical energy;
— excessive reduction in voltage in the circuit of sources and consumers of electrical energy;
- short circuit of wires and insulated parts and components of devices to the body (ground) of the car.

It is advisable to start searching for the cause of the malfunction by checking by hand the secure fastening of the wire lugs on the terminals of electrical devices, since a significant part of the malfunctions in the electrical equipment system occurs when the fastening of these lugs is loosened. At the same time, the resistance in the circuit increases, the temperature of the terminals increases, and when the car moves due to vibration, the contact in the circuit is even broken.

A break in the circuit of sources and consumers of electrical energy occurs due to melting of a fuse, opening of contacts in a thermobimetallic fuse, rupture of wires, loose fastening of wire tips on the terminals, broken contact in the plug connection of wires, broken contact in switches and switches, broken circuit in consumers (burnout filament in a lamp, burnout of an additional resistor or electric motor winding, etc.).

Due to the widespread use of electronics in cars, fuses, which are installed in separate blocks or blocks, have become widespread. When troubleshooting a circuit, it is convenient to use diagrams and tables with a list of consumers protected by numbered fuses (the tables are given in the vehicle’s factory operating instructions). In order to ensure that the fuse is working properly, it is necessary to turn on the consumers protected by this fuse one by one. If at least one consumer is working, the fuse is good.

If a fuse insert has melted, then before replacing it with a new one, it is necessary to eliminate the malfunction that caused the melting of the insert. If there is no spare insert, you can solder a copper wire with a diameter of 0.18 mm to the contacts of the insert for a current of 6 A, 0.23 mm for a current of 8 A; 0.26 mm - for 10 A, 0.34 mm - for 16 A, 0.36 mm - for 20 A.

Before installing a new insert, it is necessary to bend the terminals of the holder, which will ensure reliable contact between the insert and the holder. Using the example of a simple electrical circuit of a GAZ-bZA car, we will consider searching for broken wires and other faults in the on-board network (Fig. 2). For example, the headlights do not light up.

Rice. 2. Electrical diagram of the GAZ -63A car: 1 - emergency oil pressure warning lamp sensor; 2- oil pressure gauge indicator sensor in the lubrication system; 3- breaker-distributor; 4 - transistor switch; 5 - engine overheat indicator sensor; 6 - engine coolant temperature indicator sensor; 7 - additional resistors; 8- starter activation relay; 9- turn signal switch; 10 - control lamp for turning on the high beam headlights; 11 - engine compartment lamp; 12 - wiper motor switch; 13-turn indicator switch; 14 - brake light switch; 15 - foot light switch; 16 - central light switch; 17- plug socket for a portable lamp; 18, 19 - thermobimetallic fuses; 20-ignition switch; 21 - heater electric motor; 22 - dome lamp switch; 23 - fuel level sensor; 24 - lamps for lighting control and measuring instruments; 25 - trailer socket

Consider the current path in the headlight circuit. Positive terminal of the battery - terminal of the starter traction relay - ammeter - terminal "AM" of the ignition switch 20 - fuse 18 terminal "1" of the main light switch 16 - terminal "4" of the switch 16 - terminal of the foot light switch 15 - output terminal of the foot switch ( one of two depending on the position of the switch) - terminal of the connecting panel (block) - filament of the headlight lamps - car body - negative terminal of the battery.

To determine an open circuit in this circuit, connect one wire from a test lamp * or a voltmeter to the car body, and with the end of the other wire touch the terminals of consumers, devices, switches and connecting panels included in this circuit, starting from the positive terminal of the battery, in the sequence considered current paths. Before connecting the control lamp to terminal “4” of the main light switch, you must set the switch handle to position II. When connecting a test lamp to the output of the foot switch, you must press its rod 2-3 times.

When the test lamp goes out (or the voltmeter needle deviates to zero), this will indicate that the circuit has an open circuit in the area from the previous point where the test lamp (voltmeter) wire touched to this point in the circuit being tested.

A broken wire can be determined in another way. To do this, you need to disconnect the ends of the wire being tested and connect it in series with a lamp (or voltmeter) to the battery. If there is a break, the indicator lamp will not light up.

If necessary, check the serviceability of the lamps without removing them from the headlights. To do this, a conductor is used to connect the positive terminal of the battery to the corresponding terminal of the connecting panel, to which the conductors from the lamps being tested are connected. A working lamp will light up.

If the lamp in the headlight is working properly, it, like the control lamp, will burn with incomplete intensity. The control lamp lights up at full intensity in the event of a short circuit to the housing electrical circuit in the headlight.

Attention!

It is strictly prohibited to check the serviceability of the electrical energy consumer circuits of the vehicle “by spark,” i.e., by shorting the wire to the body, since even a short-term short circuit can cause damage to semiconductor devices of electrical equipment, printed circuit boards mounting blocks, etc.

An unacceptable voltage drop in consumer circuits is created due to an increase in resistance at the points where wire lugs are attached to the terminals of electrical energy sources and consumers, devices, connecting panels, as well as in the plug connections of conductors. Resistance increases due to oxidation of the contacting surfaces of parts, as well as a violation of the strength of fastening of wire tips.

For example, when the terminals of the battery and the tips of the starter wires are oxidized, at the battery terminals due to a sharp increase in resistance in the circuit, even when the starter and battery are in good condition, the current in the circuit is significantly reduced, and therefore the torque on the starter drive gear and the armature rotation speed are reduced. . As a result, the starting speed of the engine crankshaft is not ensured and it does not start.

Another example. In case of contact failure in the connection of wires at the terminals, oxidation or loose contacts in the light switches, the lamps do not light up or significantly reduce the light intensity. Similar phenomena are created in other circuits of the vehicle’s on-board network. As a rule, heating increases in places where the wires are loosened, which is a sign of this malfunction. Increasing the temperature of parts accelerates their oxidation. The voltage drop in volts in various circuits of electrical energy consumers is determined as follows. First, the voltage is measured at the terminals of the battery, then, for example, at the terminals of the connecting panels in the lighting and light signaling circuit. The voltage difference between the source and the terminals of the connecting panels will be the magnitude of the voltage drop in the circuit under study.

The permissible voltage drop in the electrical circuit of headlights, sidelights, direction indicators, and light signaling lamps should not be more than 0.9 V for a 12-volt system and 0.6 V for a 24-volt system. At each wire lug riveting, the voltage drop should not exceed 0.1 V.

The short circuit of conductors and parts of apparatus and electrical equipment to the car body occurs due to the destruction of insulation due to mechanical or thermal damage. Since the conductors connecting sources and consumers of electrical energy have very low resistance, when they are shorted to the car body, current will flow through them great strength, causing the fuse to open the circuit. If it is not protected by a fuse, then the insulation is destroyed and the conductors melt and thermal damage to the ammeter occurs. This may cause a fire.

To determine whether a wire is shorted to the car body, it is necessary to disconnect the ends of the wire being tested from the terminals and connect one end in series with a lamp or voltmeter to the positive terminal of the battery. If there is a short to the housing, the lamp will glow (dimly or brightly depending on the degree of the short circuit), and the voltmeter needle will show the voltage at the battery terminals.

Failure of electrical energy consumers connected to a group thermobimetallic fuse most often occurs due to the opening of its contacts when this circuit is closed to the car body. To check, you should press the button of this fuse, and if its contacts open again, then there is a short circuit to the car body in the circuit of connected consumers. In this case, you need to turn off the consumers, press the fuse button, and then turn on the consumers one by one. Correct consumers will work. If, when turning on any consumer, the fuse contacts open, then there is a short circuit to the housing in the circuit of this consumer.

On many modern cars a mounting block is installed in the on-board network, in which all fuses and most of various relays. In Fig. Figure 3 shows the mounting block 17.3722 of the VAZ-2108 car, in which fuses (Pr1 - Pr16) and relays (K1 - KN) are installed. There are also resistors R1 and R2, diodes D1 and D2 of type KD215A, diodes DZ, D4 and D5 of type KD105B. The block has 11 plug blocks (Ш1-Ш11) for connecting bundles of wires.

Rice. 3. Mounting block of fuses and relays 17.3722 for VAZ -2108:

Rice. 4. Internal connection diagram

If, in the event of a malfunction, there is a need to check the corresponding circuit in the mounting block, it is necessary to general scheme electrical equipment of the car or the power supply circuit of a faulty consumer, find the numbers of inputs and outputs of this circuit in the mounting block. Using the circuit diagram of the mounting block (Fig. 4), you can trace the switching of this circuit inside the block. Then, using Fig. 3, b, find these pads and plugs on the block and use a test lamp or ohmmeter to check the circuit. Since some circuits include diodes, the “+” of the current source, test lamp or ohmmeter is connected to the input, and the “-” to the output of the circuit. If the circuit being tested includes a fuse or a relay, then to test the circuit you must first check the fuse and install jumpers instead of the relay: one instead of contacts and the other instead of a coil.

The entry, for example, Ш1-2 means: plug block No. 1, pin No. 2. The entry K1.15-K11 in the “Contacts...” column means that you need to connect plugs “15” and “1” of relay socket K1 with a jumper. Jumpers can also be installed instead of a faulty relay.

For example, you need to check the brake light circuit on a VAZ -2108. Having found the brake light switch on the general electrical diagram, we see that two wires go to it: white and red (purple). The first of them goes into block Ш4, the second - into block Ш2.

Rice. 5. Checking the control lamp mounting block with an ohmmeter

Same place or separately wiring diagrams, usually given in repair manuals, we see that the white wire is connected to terminal No. 10, and the red wire to No. 3. According to the switching diagram of the mounting block, also available in the repair manuals, we find that power is supplied from pin Sh4-10 and it, in turn, is connected through the fuse Prb to the closed pins Sh8-5, Sh8-6 and Sh8-7, two of which are used to supply power from the generator (battery). There we also find that through pin Ш2-3 and then Ш9-14, current is supplied to the lamps in the rear lights.

If the fuse is working (usually you need to verify this immediately, using the fuse table, located, for example, in the “Car Operation Manual”), connect a test lamp (Fig. 5) to terminals Ш4-10 and Ш8-7 (Ш8-5, Ш8-6). Similarly, we check the circuit of the mounting block between terminals 1JJ2-3 and Ш9-14. If there is a break in the circuit, you need to disassemble the block and solder the broken section of the board (you can solder a conductor parallel to it) or replace the printed circuit boards.

Another example: you need to check the low beam circuit of the right VAZ -2108 headlight in the mounting block. According to the fuse table, we find that the low beam filament of this headlight is protected by fuse Pr 16. In Fig. 4 it can be seen that this fuse, on the one hand, has an output to Shch5-6 and Sh7-4 (empty), and on the other hand, it is connected through the contacts of the KN relay with power (pins Sh8-7, Sh8--5, Shch8-6, as and in the previous example). In turn, the gearbox relay coil is connected to terminal Ш4-12 (on the left-hand light switch) and the ground of the block - terminals ШЗ-5 and Ш10-5.

To check these circuits, instead of the relay, we install two jumpers: 30-87; 85-86. Then we connect the ohmmeter to terminals Ш8-7 (Ш8-5, Ш8-6) and Ш5-6. The resistance should be close to zero. Similarly, we connect the ohmmeter to terminals Ш4-12 and ШЗ-5 (Ш10-5).

It is obvious that using a test lamp in the first example and an ohmmeter in the second is equivalent.

On a car, to check the serviceability of the relay, for example, K11, it can be replaced with a similar one, for example, K5. If after replacing the relay the headlights turn on, then the unit is working, and the replaced relay is faulty. Instead of a faulty relay, you can leave a jumper, but keep in mind that in this case the contacts of the headlight switch will be overloaded, which will cause them to oxidize. Detailed testing of various relays is described in the relevant sections of the book.

Sources and consumers of electrical energy, together with wires and switching elements (switches and switches), make up the electrical circuit of a car. To transmit electrical energy from a source to consumers, wires are used, which, according to their insulation, are divided into low- and low-voltage wires. high voltage. For low voltage, wires of the PGVA brand (flexible vinyl automotive wire) or PGVAE (shielded) are used.

In the secondary circuit of the ignition system, special high-voltage wires of the PVV (GAZ-66) or PVS-7 (ZIL-131, Ural-375D) brand are used.

On cars, a single-wire electrical system is used, in which the second wire is replaced by metal parts of the car itself (the mass of the car).

A single-wire system halves the number of wires, greatly simplifying the circuit and reducing cost. At the same time, a single-wire system requires better insulation of wires and their fastening. If the insulation is broken, the wires may directly touch the vehicle ground, causing short circuits.

When inspecting and maintaining a vehicle, it is necessary to carefully check the condition of the wire insulation and eliminate the causes of damage to the wires (rubbing on sharp edges, excessive sagging, contact with flammable and lubricants). Special attention When installing electrical equipment, it is necessary to pay attention to the reliability of the connection of their housings with the mass of the vehicle. This is achieved by cleaning the seats from dirt, corrosion and paint, as well as by securely fastening the wires connecting the instrument housings to each other and to the vehicle ground.

For ease of installation and protection of the wires from mechanical damage, they are bundled with cotton braiding. Wires (bundles) are fastened using staples, the distance between which should be 30-40 cm.

To ensure good electrical contact and simplify the installation of circuits, plug-in connections of wires to device terminals are now widely used. To find it faster the right wire in a common bundle of wires, external insulation made in color. This makes it easier to install wires, as well as find and eliminate faults in electrical circuits -

In Fig. 1 shows a complete diagram of the electrical equipment of the GAZ -66 car. Knowledge of the circuit and current paths is necessary for quickly detecting and eliminating faults in electrical equipment that arise during vehicle operation.

Studying the circuit is easier if you keep in mind some general provisions, the main ones being the following:
1. First of all, it is necessary to identify the circuits connecting the battery, generator, relay regulator, ignition switch, ammeter and central light switch. All current consumers are connected to one of the listed devices.
2. Determine the composition of each circuit of electrical equipment.
3. Find the system devices on the diagram and on the car and study the order in which the devices are connected to each other.
4. Trace the path of the current in the circuit and understand the physical meaning of its effect on a particular consumer. It must be borne in mind that each consumer (with the exception of electric starting system devices) can be powered by current from both the battery and the generator. When the engine is idle and operating at low crankshaft speed, when the generator voltage is less than the battery voltage, all consumers are powered by the battery. When the engine operates at medium and high crankshaft speeds, all consumers, including the battery, receive energy from the generator.
5. Only the discharge and charging current of the battery passes through the ammeter. The generator current that goes to power consumers does not pass through the ammeter.
6. The circuit of each consumer starts from the “+” terminal of the current source and ends with the “-” terminal of the same source.
7. The current path to all consumers, except the charging circuit, ignition system and electric starting system, passes through fuses.

Consider, for example, the current path in the primary circuit of the ignition system of a GAZ -66 car from the battery and from the generator. To turn on this circuit, you must use the ignition key to close terminals AM and short circuit of the ignition switch. In this case, the current flows like this: terminal “+” of the battery - starter clamp - ammeter - ignition switch - additional resistor - terminal K of the transistor switch - primary winding ignition coils - unnamed terminal of the transistor switch - transistor switch - ground - battery switch - terminal “-” of the battery.

The current path of the primary circuit of the ignition system from the generator: terminal “+” of the generator 12 - terminal “+” of the ammeter 45 - terminal AM of the ignition switch 46, and then the same path remains as when powered by a battery, only the current flows from ground to terminal "-" of the generator.

Rice. 1. Electrical diagram of the GAZ-66 car:
1 - sidelight; 2 - headlight; 3 - connecting panel; 4 – sound signal button; 5 - sound signal; 6 - engine compartment lamp; 7—special flashlight; 8 - fuel level indicator; 9 - voltage regulator; 10 - coolant temperature indicator; 11 - control lamp for coolant temperature; 12 - generator; 13 - heater motor switch; 14 - heater electric motor; 15 - radiator coolant temperature warning lamp sensor: 16 - engine coolant temperature sensor; 17 - transistor switch; 18 - damping resistance; 19 - spark plug; 20 - ignition coil; 21 - distributor; 22 - right fuel level sensor fuel tank; 23 - sound signal switch; 24 - body lamp switch; 25 - body lamp; 26 - push-button heater fuse; 27 - control spiral; 28 - spark plug switch; 29 - electric heater fan; 30 - glow plugs; 31 - additional resistor; 32 - fuel tank sensor switch; 33 - additional starter relay; 34 - cabin ceiling; 35 - lamp switch; 36 - turning headlight switch; 37 - instrument panel lighting lamp; 38 - oil pressure indicator; 39 warning lamp for emergency oil pressure; 40-turn signal indicator lamp; 41, 44 - oil pressure sensors; 42 - wiper motor switch; 43 - turning headlight; 45 - ammeter; 46 - ignition switch; 47 - push-button fuse; 48 - electric windshield wiper motor: 49 - plug socket; 50 - breaker, 51 - direction indicator switch; 52 - brake light switch; 53 - control lamp for high beam headlights; 54 - central light switch; 55 - starter; 56 - solenoid valve switch; 57 - solenoid valve; 58 - battery switch; 59 - battery; 60 - wire connector; 61 - trailer socket; 62 - back light; 63 - fuel level sensor of the left fuel tank; 64 - detachable connections; 6!5 - sound alarm relay; 66 - foot light switch, symbol colors: B - white; K - red; F - yellow; 3 - green; KOR - brown; A - black; G - blue; O - orange; P - pink; F - purple; C - gray

Typical reasons causing interruptions and failures in the operation of electrical equipment systems and circuits include:
— weakening of contact in circuit connections;
— oxidation of contacts and contact connections;
— damage to insulation and short circuit to ground of wires and current-carrying elements of electrical equipment;
— lack of reliable connection of instrument housings with the vehicle’s mass; circuit breaks.

It is convenient to detect the location of a break or short to ground using a test lamp (A12-1 or A12-3) by sequentially checking all sections of the circuit. The nature of the fault in the circuit (open or short circuit) is indicated by the ammeter arrow when connecting this circuit to the battery.

A complete diagram of the vehicle's electrical equipment is given in each instruction manual (manual) for operating this vehicle. This makes it easier to find a fault if it occurs.

TO category: - 1Domestic cars

Process control circuits consist of open channels through which information about the progress of the technological process enters the facility control point.

Process control systems have a huge number of characteristics (or states) production devices), about which only two-position information is sufficient for the operator to carry out the normal technological process (parameter is normal - parameter is out of norm, mechanism on - the mechanism is off, etc.).

These characteristics are monitored using signaling circuits. In most cases, these circuits make more extensive use of electronic relay contact elements with light and sound signaling of deviations in characteristics.

Light signaling is carried out using various signal fittings. With all this, the light signal can be reproduced with a flat or flashing light, or by glowing lamps in an incomplete channel. Sound alarm usually done with the help of bells, beeps and sirens. In some cases, signaling the activation of protection or automation can be carried out using special signaling indicator relays-blinkers.

Alarm systems are developed specifically for of this object, therefore there are always their principle diagrams.

Signaling principles according to their intended purpose can be divided into the following groups:

1) position (state) signaling circuits - for information about the state of technological equipment (“Open” - “Closed”, “On” - “Disabled”, etc.),

2) process alarm circuits that provide information about the state of such process characteristics as temperature, pressure, flow, level, concentration, etc.,

3) command signaling schemes that allow you to transmit various instructions (orders) from one control point to another using light or sound signals.

Based on the principle of action they distinguish:

1) alarm schemes with personal pickup of an audio signal, characterized by sufficient simplicity and the presence for each signal of a personal key, button or other switching device, which allows you to turn off the sound signal.

Such schemes are used for signaling the position or state of individual units and are not sufficiently applicable for mass process signaling, because in them, immediately with the sound signal, the light signal is usually turned off,

2) schemes with a central (general) sound signal pickup without repeating the action, equipped with a single device with which you can turn off the sound signal while maintaining a personal light signal. The disadvantage of schemes without repeated sound signal is the impossibility of receiving a new sound signal before the contacts are opened electronic devices, which caused the first signal to appear,

3) schemes with central pickup of an audio signal with repetition of the action, which differ from previous schemes by the ability to re-issue an audio signal when any alarm sensor is triggered, regardless of the state of all other sensors.

Based on the type of current, a distinction is made between constant and alternating current circuits.

In the practice of developing technological process automation systems, various signaling schemes are used, differing both in structure and methods of constructing their individual components. The choice of a more optimal principle for constructing a signaling circuit is determined by certain criteria for its operation, also technical requirements requirements for lighting equipment and alarm sensors.

Position signaling circuits

These circuits are produced for devices that have two or more operating positions. It is not possible to show and analyze all the signaling schemes encountered in practice, and also to give an analysis of the reliability and effectiveness of each because of their abundance. Therefore, more appropriate and often repeated in practice variants of schemes will be examined further.

The most widespread are two options for constructing position (state) signaling circuits: technological devices:

1) signaling circuits combined with control circuits,

2) signaling circuits with power supply independent of control circuits for a group of technological devices of the same purpose or for various purposes.

Signaling circuits combined with control circuits are usually made in this case, when switchboards and control panels do not have mnemonic diagrams, and the required area of ​​switchboards and consoles allows the use of signaling equipment without limiting its size, allowing direct power from control circuits. Signaling the position (state) of technological devices in such circuits can be carried out by one or two light signals with the lamps lighting up evenly.

Circuits built with one lamp usually indicate the switched on state of the mechanism and are used in conditions where the technological process and reliability allow such signaling.

It must be emphasized that such schemes do not provide equipment that allows the lamps to be inspected from time to time during use. The absence of such control in the event of a lamp burnout can lead to incorrect information about the state of the mechanism and disruption of the normal course of the technological process. Therefore, if the occurrence of incorrect information about the state of the technological process is not allowed, circuits with two-lamp signaling are used.

Position signaling schemes with the introduction of two lamps are also used for devices such as shut-off devices (latches, flaps, flaps, dampers, etc.), because to ensure reliable signaling of two operating positions (“Open” - “Closed” ") of such devices using one lamp is actually difficult.

Rice. 1

Rice. 2 a - turning on the lamps through the block contacts of magnetic starters, b - bringing the circuit to a form that is comfortable for reading, c - if the position of the control key does not correspond to the position of the controlled mechanism, the lamp flashes, d - if the control key does not correspond to the position of the controlled mechanism, the lamp glows with incomplete heat, LO - signal lamp “Mechanism is disabled”, LV, L1 - L4 - signal lamps “Mechanism is on”, V, OV, OO, O - positions of the CU control key (respectively “On”, “Operation on”, “Operation off”, “Disabled”), ShMS - flashing light bus, ShRS - steady light bus, DS1, DS2 - additional resistors, PM - block contacts magnetic starter, KPL - button for checking lamps, D1 - D4 - separating diodes

Let's sum up some results. Circuits with power control independent of circuits (see Fig. 2) are mainly used to signal the position of various technological devices on mnemonic circuits. In such circuits, compact signal equipment is used to a greater extent, designed to be powered by alternating or constant current with a voltage not exceeding 60 V.

The signal can be reproduced using one or two lamps, glowing with even or blinking light (see Fig. 2, c) or incompletely glowing (see Fig. 2, d). Such light signals are usually used in schemes that signal a discrepancy in the position of an organ remote control mechanism, in this case the CU control key, the actual position of the mechanism.

In position signaling circuits with independent power control circuits, implemented using a single lamp, equipment is usually provided for monitoring the serviceability of signal lamps (see Fig. 2, a).

Process signaling diagrams

Process alarm circuits are designed to alert service personnel about a violation of the normal course of the technological process. The process alarm is displayed by a steady and flashing light and is usually accompanied by an audible signal.

The intended purpose of the alarm can be warning or emergency. This division ensures different reactions service personnel on the nature of the signal that determines one or another degree of disruption of the technological process.

The greatest use has been found in process alarm circuits with central audio signal pickup. They make it possible to receive a new sound signal before the contacts that caused the previous signal are opened. The introduction of various relay and signaling equipment, different voltages and types of current does not actually change the principle of operation of the circuits.

Technological processes require positional control of a huge number of characteristics, and a corresponding feature of process alarm circuits is the presence of common circuit units in which information coming from many on-off process sensors is processed.

Information from these nodes is issued in the form of sound and light signals only about those parameters whose values ​​are out of the norm or are needed for control technological process. Thanks to common components, the need for equipment and the costs of production automation are reduced.

Depending on the number of signaled characteristics light alarm can be done with a steady or flashing light. When signaling many characteristics (more than 30), circuits with flickering of the received signal are used. If the number of characteristics is less than 30, use schemes with even light.

The method of operation of process alarm circuits is almost always similar: when a parameter deviates from given value or exceeding the permissible level, sound and light signals are given, the sound signal is removed with the sound signal release button, the light signal disappears when the difference between the parameter and the permissible value decreases.

Rice. 3. Process alarm circuit with isolating diodes and flashing light: LKN - voltage control lamp, Zv - bell, RPS - warning relay, RP1-RPn - intermediate relays of personal signals, switched on by contacts of sensors D1 - Dn of process control, LS1 - LSn - personal lamps , 1D1-1Dn, 2D1-2Dn - decoupling diodes, KOS - signal testing button, KSS - signal pickup button, ShRS - level light bus, ShMS - flashing light bus

Rice. 4. Alarm circuit using a pulse pair instead of a flashing light source

Process alarm circuits with an audible signal dependent on the light signal are used only for warning signaling of the state of non-critical process characteristics, because in these circuits the signal loss is likely if the signal lamp is faulty.

You may encounter process alarm circuits with personal audio signal pickup. The circuits are built with the introduction for each signal of an independent key, button or other switching device that turns off the sound signal, and is used to signal the state of individual units. Immediately with the sound signal, the light switches off.

Command signaling circuits

Command signaling provides one-way or two-way transmission of different command signals in situations where the introduction of other types of communication on technical level impractical, and in some cases difficult or unrealistic. Command signaling schemes are ordinary and usually do not cause difficulties in reading them.

Rice. 5. Example of principle electronic circuit command signaling (a) and interaction diagrams (b and c).

In Fig. 5, and a diagram of a one-sided light and sound alarm is shown for calling commissioning personnel to workplaces. The call is made from the workplace by pressing the call buttons (KV1-KVZ), which on the dispatcher's panel turn on light (L1-LZ) and sound (Sv) signals. Dispatcher, setting by light signal the number of the workplace from which the signal was received, by pressing the KSS signal release button, brings the circuit to the initial state. Relays RP1-RPZ and RS1-RSZ are intermediate.

Electrician school

Car electronics

V. KHROMOV, Krasnoyarsk
Radio, 2002, No. 2

The sensor in control devices is usually a current-measuring resistor, which often limits their use, for example, due to big fall voltage in the controlled circuit and wasted power dissipated by the current sensor. These disadvantages are minimized, but by complicating the circuit.

The proposed device uses a different method of controlling the current in the lamp circuit - relay, using the hysteresis of the electromagnetic relay and the starting current pulse inherent in the incandescent lamp when it is turned on. This method allows you to reduce the voltage drop in the controlled circuit to a negligible value. Unlike the previously described devices, it indicates three states of the lamps.

Fundamental brake light controller circuit diagram shown in Fig. 1. The current sensor is a reed relay K1, the winding of which is connected in series to the circuit of signal lamps HL2, HL3. A controlled pulse generator with a period of about 0.5 s is assembled using logic elements DD1.1, DD1.2. Element DD1.3 is an electronic switch that operates with a time delay. Transistor VT1 is a current amplifier loaded by LED HL1.

When the brake pedal is not depressed and the SF1 contacts associated with it are open, only the pulse generator operates. The lower input of element DD1.3 is connected through resistors R4, R5 to common wire. Therefore, pulses do not pass through this element and its output is at a high level. The low level at the output of the inverter DD1.4 closes the transistor VT1 - the HL1 LED is turned off.

When you press the brake pedal, it closes contacts SF1 and current from the on-board network begins to flow through the car's fuse FU1, winding K1 and lamps HL2, HL3. If both lamps are in good working order, then their starting current, although short, is almost ten times greater than the rated current, leads to reliable operation of relay K1.

Contacts K1.1 of the reed switch close, the supply voltage from the resistive divider R1R2 through the diode VD1 is supplied to the combined inputs of the element DD1.1 and blocks the operation of the generator, and a high level is fixed at the output of the element DD1.2. The values ​​of resistors R1, R2 are chosen in such a way that, at a relatively small current through the reed switch, the voltage removed from the divider corresponds to a unity level.

After a short period of time, the current in the lamp circuit will decrease to the rated value, but the reed switch K1.1 remains closed, since the rated current of the two lamps HL2 and HL3 more current releasing relay K1.

After the time T=R4-C2 (about a second) has elapsed from the moment the brake pedal is pressed, the voltage on capacitor C2 increases to the switching threshold of element DD1.3. A low level appears at the output of the element, and a high level appears at the output of the inverter DD1.4, opening transistor VT1. The LED turns on, indicating that the lamps are working properly.

After releasing the pedal, lamps HL2, HL3 go out, winding K1 is de-energized and the reed switch opens, allowing the generator to operate. Its pulses periodically close transistor VT1, so the LED blinks.

Capacitor C2 is discharged through resistor R4, relay winding K1 and lamps HL2, HL3, and after some time, when the voltage on it decreases to the switching threshold of element DD1.3, the pulses will stop passing to the inverter input. The transistor will not open, the LED will go out. This indication mode allows you to verify that the lamps are working properly and at the same time that the generator is operating.

If, when you press the brake pedal, one lamp turns out to be faulty (burnt out or the contact in the socket is broken), then the relay will first operate under the influence of the starting current of the second - working - lamp. But rated current one lamp is not enough to keep the reed switch closed, and it opens. This process lasts several tens of milliseconds and does not affect the display in any way. After a second, element DD1.3 will begin to transmit pulses from the generator and the LED will begin to blink. When releasing the brake pedal, the process is similar to that discussed above.

If both lamps fail one after the other or their power supply circuit is interrupted, the reed switch will not close at all and the LED will blink, as with one faulty lamp.

It happens that fuse FU1 blows (or its contacts oxidize). Then the supply voltage is not supplied to the device and when you press the brake pedal, the indication is completely absent.

You can, of course, use an incandescent lamp as an indicator, but the reliability of an LED is higher.

The controller uses resistors C2-ZZN, OMLT; capacitors are ceramic, KM-5, KM-6, and oxide capacitors are K50-35. Instead of K561LA7, the KR1561LA7 microcircuit is suitable. We can replace the KT315G transistor with any silicon one npn transistor, for example, KT501G-KT501E.

Reed switch - KEM-1; its winding contains nine turns of copper winding wire PEV-2 0.8. If a smaller reed switch is used, then the number of turns must be reduced by approximately 1.5...2 times.

The X1 connector socket is RGN-1-3, and the insert is RSh2N-1-17. When replacing a connector with another, it is necessary to take into account its operating conditions - vibration and shock, increased humidity and temperature. Connectors X2 and X3, designed for high current, are used for automobiles; it is permissible to replace them with screw terminals.

It is better to replace the AL307M LED with a brighter L-53SRC-E from Kingbright.

Structurally, the device is assembled on a circuit board with wiring MGTF wire with a cross-section of 0.07 mm 2 and placed in a suitable insulating box. The connector block X1 is fixed in its end part.

To make relays, they are selected or glued together from thick paper tube so that the reed switch fits easily into it. Rigid tubes made of any other non-magnetic material - metal or plastic - are also suitable. A winding is wound onto the tube so that the axial length of the winding is several less length reed switch cylinder, and lubricate epoxy glue. The leads are shortened to 8...10 mm and tinned for mounting on the board.

The conductors connecting the relay winding to the vehicle's electrical system must have a cross-section no less (or better, a little larger) than that of the wires to the lamps. The controller should be placed as close as possible to the SF1 contacts and securely fastened. The LED is mounted on the instrument panel.

When setting up a controller connected to a car, the required sensitivity of the relay is selected by moving the reed switch relative to the winding. The reed switch is fixed in the optimal position in the tube with drops of glue.

In Fig. 2 presented controller circuit for low and high beam lamps. Here, a clock pulse generator with a repetition period of about 0.5 s is assembled on the Schmitt trigger DD1.1, a buffer-inverter is assembled on the trigger DD1.2, and electronic switches with a time delay are assembled on the triggers DD1.3, DD1.4, similar to those used in the previous device, for the high and low beam channels, respectively. Transistors VT1, VT2 serve as current amplifiers, their load is a two-color LED HL1. Current sensors K1 and K2 are the same reed relays. The generator operates continuously, regardless of the state of the reed switches K1.1 and K2.1.

Since both channels are the same, we will consider the operation of only the low beam channel. From the pulse generator, the clock sequence is supplied through the inverter DD1.2 to the upper input of the trigger DD1.4 in the circuit. Since the lower input of the trigger is connected to the housing through the relay winding K1, fuses FU1, FU2 and low beam lamps EL1, EL2 (as well as through resistors R5, R8), its output is high. Transistor VT2 and LED HL1 are turned off.

When lamps EL1, EL2 are working properly, turning on the low beam causes voltage to appear at connector X2, as a result of which they turn on. Their starting current triggers relay K1, and through reed switch K1.1 the voltage is supplied to the upper input of the Schmitt trigger DD1.4, but the trigger does not change its state. After the rated current through the lamps has been established, the reed switch remains closed.

After about a second, the voltage on the capacitor SZ, increasing, reaches high level at the input of the trigger, it switches to the zero state. Transistor VT2 opens and turns on the “green” LED of the HL1 assembly.

When the low beam is turned off, the supply voltage at connector X2 disappears, the lamps turn off, and the relay opens reed switch K1.1. Pulses from the generator periodically switch the DD1.4 trigger, which causes the LED to blink green. After some time, the capacitor SZ will discharge and the Schmitt trigger DD1.3 will again block the passage of pulses from the generator to the base of the transistor VT2.

If at least one lamp (or its fuse) burns out, turning on the low beam will cause the green signal to start flashing after a second, indicating to the driver that a malfunction has occurred. This controller cannot accurately indicate the reason for the lack of glow of the lamp.

The second channel - high beam - works similarly, only the indicator is the “red” LED of the HL1 assembly.

Instead of KT209G, any transistor from the KT503 series can be used in the device. It is advisable to replace the ALS331A LED with an analogue of increased brightness, for example, L-59EGC from Kingbright. With the KR1561TL1 microcircuit, which allows a higher supply voltage, the controller will work more reliably.

Relays K1 and K2 use the same KEM-1 reed switches. Relay winding K1 contains 6 turns, and K2 has 2 turns, wound with PEV-2 wire with a diameter of at least 1.5 mm.

The circuit board of the device is placed in an insulating box suitable sizes, which is mounted near the high and low beam relay of the car. Relays K1 and K2 are connected to the electrical system with four flexible insulated wires cross section of at least 2 mm 2.

The operation of the described controllers on a VAZ-2106 car for several years has shown their reliability and ease of use.

LITERATURE
1. Chuikin A. Stop signal under reliable control. ≈ Behind the Wheel, 1995, No. 9, p. 80.
2. Bannikov V., Varyushin A. Controller for brake light lamps. ≈ Radio, 1996, No. 8, p. 52.
3. Alekseev S. Monitoring the serviceability of signal lamps. ≈ Radio, 1997, No. 5, p. 42, 43.

Signal lamps serve for light signaling of the state of the controlled circuit. Using them, you can quickly determine the presence of voltage at the input to the panel, whether any circuit is turned on or not, etc. They are very easy to operate and understand for an untrained person. If the lamp lights up, then there is voltage in the network, and if not, then there is no voltage. If the distribution panel has a transparent cover, then the LS-47 signal lamps create a very beautiful illumination there. It's like an added bonus.

Signal lamps LS-47 are produced different manufacturers. These are IEK, EKF, TDM and others. They are modular and very similar to circuit breakers. Only instead of a switch, they have the lamp itself. They are mounted on a DIN rail. This design allows them to be installed in any distribution panel next to other modular devices. LS-47 is a neon lamp with a current limiting resistor connected in series.

Very simple. It has two outputs (contacts) to which “phase” and “zero” are connected.

Here is the diagram from the device passport...

Also, the connection diagram is often shown on the signal lamp body itself...

Here are a couple of diagrams of a single-phase distribution board, where a signal lamp is connected to the input. It can be used to monitor the presence of input voltage.

You can also visually check the presence of voltage in three-phase network. Sometimes there are emergency situations, when one of the phases breaks, somewhere on the contact network. If your house has a 3-phase input, and the load is single-phase and distributed into three groups, then if one phase fails, only some of the electrical appliances will not work. This is often misleading. For example, sockets and lights may work in some rooms, but not in others. In such a situation, a search begins for the place in a given line where a phase or zero has disappeared (broken). In such a situation, if there is an LS-47 signal lamp at the input, you can immediately visually determine that the voltage has simply disappeared in one of the phases. This means the problem is not in your home, but somewhere in the contact network.

Here is a diagram of a three-phase distribution board, where LS-47 signal lamps are connected to the input on each phase.

So we figured out the connection diagram for the LS-47 signal lamp.

Do you use such lamps anywhere in your home?

Let's smile:

Two dogs are talking in Pavlov's clinic. One says:
- Look, there are men coming who react to the light of a light bulb. As soon as a light comes on, they serve food.

The schemes that allow you to extend the life of daylight (LDS) are described. They certainly deserve attention, they attract with their simplicity, accessibility and can be recommended for repetition. But when repeating these circuits, one must keep in mind that the LDS filament, which remains “live,” operates with an overload, since the burnt-out filament is shunted by a “wire jumper.” This forced operating mode, due to the reduction in the resistance of the incandescent filament chain by half, leads to its rapid wear and tear, and it fails. In addition, the "resuscitation" given in , requires additional installation start button, so when controlling the LDS using a wall switch, a problem arises - where to place this start button to turn on the lamp installed on the ceiling? ...

For the "Non-contact phase indicator" circuit

If you take a neon lamp by the glass body and touch one of its terminals phase wire power supply, the lamp begins to glow. The current causing the glow flows through electrical capacitance between the fingers and the internal electrodes of the lamp. This result can be used to make a simple phase wire indicator. To one of the conclusions lamps solder a metal pin. You should choose the output that produces the brightest glow. On the plinth lamps put on a slightly stretched PVC tube. The cavity in the tube is filled with epoxy glue using a cocktail straw (see picture). The indicator can use a wide variety of small-sized lamps: TN-0.5; MH-6, thyratron MTX-90, etc. The sensitivity of the indicator is slightly lower than that of a traditional indicator with a resistor. S.L. Dubovoy, St. Petersburg, Russia. ...

For the circuit "Network voltage level indicator"

I suggest the simplest signaling device voltage in the network goes beyond the established limits. It is shown in the picture. Resistor R2 is selected so that the neon lamp HL1 is turned on only when the network voltage is more than 190 V. And by selecting resistor R4, HL2 is turned on only at a voltage exceeding 240 V. Thus, at a voltage less than 190 V they are turned off, in the range of 190.. .240 V one of them shines, and at an even higher voltage both of them shine. Neon lamps can be used in the device lamps not only the type indicated on the diagram, but also any others with an operating current of no more than 1...2 mA.Ya. MANDRIK, Chernivtsi, Ukraine...

For the diagram "On the use of fluorescent lamps with burnt-out filaments"

Often published in amateur radio magazines various schemes using fluorescent lamps with burnt-out filaments. The author has tested all such schemes in practice. Using the experience of these tests and a number of modifications, the author settled on the diagram shown in the figure. Throttle Dr1 should only be used for the corresponding power fluorescent lamp. If you don’t have such a throttle at hand, I suggest the following option: for lamps 20 (18) W connect two 40-watt chokes in series; For lamps 40 (30) W - two 80-watt chokes in series or two 20-watt chokes in parallel. Capacitors should be used paper type KBG(I) or similar with an operating voltage of at least 600 V, since at the moment of switching on these are the voltages that appear on them. This ensures that the lamp ignites. Then the voltage drops to 250-270 V, and the fluorescent lamp lights steadily. The described scheme has one drawback: The lamp must be turned over once or twice a year (the signal is unstable ignition of the lamp). But the described scheme switching on has a number of advantages: burnt-out lamps are used, which are usually thrown away; lamp is powered DC, which is beneficial for the eyes; high durability (the author has some lamps have been working for 15 years). 0. G. Rashitov. Kiev City...

For the "Hidden Wiring Detector" circuit

Consumer ElectronicsDetector hidden wiring One of the simplest devices is a hidden wiring detector, shown in Fig. 1. Resistor R 1 is needed to protect the K561LA7 microcircuit from increased voltage of static electricity, but, as practice has shown, it does not need to be installed. The antenna is a piece of ordinary copper wire any thickness. The main thing is that it does not bend under its own weight, i.e. was pretty tough. The length of the antenna determines the sensitivity of the device. The most optimal value is 5...15 cm. When the antenna approaches the electrical wiring, the detector emits a characteristic crackling sound. This device is very convenient for determining location burnt out lamps in a Christmas tree garland - around it the crackling stops. The ZP-3 type piezo emitter is connected in a bridge circuit, which provides increased “crackling” volume. Figure 2 shows a more complex detector, which has, in addition to sound. There is also a printed circuit board for the gold digger and also a light indication. The resistance of resistor R1 must be at least 50 MOhm. There is no current-limiting resistor in the VD1 LED circuit. since the DD1 chip (K561LA7) copes well with this function itself. If the input currents of element D 1.1 allow, then by removing resistor R1 from the circuit shown in Fig. 2, we get a device that responds to changes in the static potential in the surrounding space. To do this, the WA1 antenna is made 50...100 cm long using any wire. Now the device will respond to the movement of the human body. By putting such a device in a bag, we get an autonomous security device that emits light and sound signals, if any manipulations occur with the bag or approximately it....

For the diagram "Indication of connecting electrical appliances to a 220 V network"

The display device allows you to control when leaving home: are electrical and radio devices turned off from the network? If any load with a power > 8 W remains switched on in the network, then both LEDs HL1 and HL2 light up (see figure). ...

For the diagram "Device for protecting filaments of incandescent lamps"

For the scheme "Protection of electric lighting devices"

Consumer electronics Protection of electric lighting devices V. BANNIKOV Moscow The article Soft load in the electrical network (Radio, 1988, No. 10, p. 61) describes a device for soft load to the electrical network alternating current. Such devices can be successfully used for switching electric lighting devices. As is clear, the resistance of the filament in a cold state is significantly less than in a heated state. This is why incandescent bulbs most often fail the moment they are turned on. With a soft connection, the current through the thread increases smoothly, without reaching an extreme value, so the eternity increases immeasurably. Automatic shutdown of radio equipment However, the implementation of the mentioned devices is associated with a number of difficulties. Firstly, the use of high-capacity oxide capacitors is required, which, for safety reasons, must be designed for a voltage of at least 400 V. This leads to a significant increase in the dimensions of the device. Secondly, the fact that the switch is built into the device itself makes it necessary to lay additional supply wires. In many cases, this complicates the design, since using an existing ready-made switch lighting fixture. (for example, a floor lamp or chandelier with a button mounted on the power cord) turns out, as a rule, impossible. The device described below allows you to circumvent these difficulties. It (see diagram) is made in the form of a two-terminal network. This allows you to place the board with its parts in any...

For the diagram "Protection of incandescent lamps"

It's no secret that halogen lamps used in cars often fail. This occurs as a result of an inrush current resulting from the fact that the filament coil in a cold state has low resistance. Here's a dazzling example: A car's halogen fog light bulb consumes 55 W in normal operation (at 12 V supply), so the filament resistance when hot will be approximately 2.6 ohms. In fact, the resistance measured with an ohmmeter is slightly more than 0.2 ohms. As a result, the current surge will be 60 A! The proposed device is used to extend the service life of incandescent lamps in cars and other low-voltage equipment. The time for smooth warm-up - entering the mode depends on the resistance of the resistor R1 and the capacitance of the capacitor C1, and with the values ​​​​indicated in the diagram it is approximately 2.5 s. Drozdov transceiver circuits The saturation voltage of the composite transistor VT1, VT2 can be set by rotating the rotor of resistor R2. This allows you to select the required time to enter the mode, depending on the load power in the range from zero to maximum delay. Transistors VT1 and VT2 must be installed on a common heat sink with an area of ​​approximately 100 cm2, with a current consumed by the lamp up to 6 A. The choice of the KT872A power transistor is not accidental. This transistor, produced by NPO Transistor (Minsk), is capable of withstanding significant current surges for a long time at an average current of up to 10 A. If switch SA1 is replaced with a jumper, and a microswitch or microbutton is connected in series with resistor R1, additional convenience appears - the absence of a powerful power switch . Its role is now performed by a power transistor. A. FILIPOVICH, Minsk region, Dzerzhinsk...