Under the new rules of the road in the sake of safety, drivers of vehicles (especially when driving outside the city) should include the day of the lights But turn them off after a stop often forget If Parking is prolonged, the battery is badly discharged In chains prevent such troubles offer a simple device, which signals that the headlights were left on while the engine is stopped, and also indicates the inclusion of the turn signal Device contains a sound generator transistors (VT1, VT2) and a threshold of the relay (K1, VD1).
Threshold the relay is activated when the voltage at the headlamps (more than 13), that is, when the engine is running When the engine is off, the threshold relay “releases” and its normally closed contacts K1 of 1 enables the alarm, of course, when the lights are turned on the Sound generator is a single-ended multivibrator the collector circuit of power transistor VT2 includes a dynamic head is the resistance 4 — 8 Ohm.
The control circuit is connected to the “+” power multivibrator through a decoupling diode VD2—VD4, the control Voltage is supplied from the wires going to the front bulb alarm turns on any car is easy to detect visually (should not connect to the bulbs—it is unreliable) Control voltage from the headlights it is best to take the relay with which they are involved, for Example, on the car VAZ-2106 is a relay located on the right side of “splash guard” in the engine compartment the Upper relay РС527 includes the headlamps and the lower far Conduit that runs to the headlight relays located in the centre coming from the relay harness wires (it is red) Having a tester or a test lamp (led), you can easily detect it when you turn on the headlights.
All the details of the alarm device mounted on a printed circuit Board is made to “split” method On this Board is easy to notice the error during installation and possible malfunction, often without resorting to the control instrument.
Fig. 1. Schematic diagram of the annunciator switch on the car headlights
Fig. 2. Printing fee alarm
Fig. 3. Wiring diagram for relay K1 to the onboard network of the car without applying the threshold
The fee together with a speaker placed in a plastic box (e.g. fishing supplies) Box is most convenient to install under the hood, near the wiper motor.
If you want the alarm worked when the headlamps dipped and main beam, you should put another decoupling diode and to submit through the voltage from the relay for these lights.
The details of the Transistors VT1—МП42Б (КТ361Б), VT2—КТ815Б (КТ817Б) relay K1—РЭС55А (passport 0302) or any other triggered at a voltage of 2.5 — 3.5 V and current of 20 mA Diodes VD2—VD4 — КД106А, D226, fl7, fl220, VD5—Д9Д (KD521) Resistors — OMLT-0,125, the capacitor—any non-polar capacity 0,068 — 0.1 UF, speaker BA1—with capacity from 0,1 to 1 watt transistor VT2, you should install the heatsink with dimensions 20×20 mm.
Set the alarm resistor R4, achieving a “comfortable” sound.
Since the battery voltage may vary within wide limits, for greater reliability of the device threshold relays should be removed, and the winding of relay K1 to connect to the electrical system after the ignition switch is turned Off the ignition — no voltage connection Point of the relay K1 is under the hood of the engine at the input of the voltage regulator For the VAZ-2106 — pin 15 Normally closed contacts K1 are connected to the headlight.
A. PARTIN, L. MARTINA, Ekaterinburg
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