12V Vehicle Electrical Wiring Tester Circuit
This little tester is useful for checking vehicle electrical circuits. Two LEDs indicate whether one of the clips is connected to the positive supply line (red) or to ground (green).
| PARTS LIST | |
| R1 | 150Ω |
| R2 | 150Ω |
| D1 | Green LED |
| D2 | Red LED |
| D3 | 6.8V 1/4W Zener Diode |
| D5 | 6.8V 1/4W Zener Diode |
The unit is powered by the vehicle battery. It is advisable to terminate the unit into two insulated heavy-duty crocodile clips. These enable connection to be made directly to the battery or to terminals on the fuse box. It is also possible to terminate it into a suitable connector that fits into the cigarette lighter socket.
IF a sharp needle is soldered to test point, it is possible to check insulated wiring, but only those that carry 12V. Although the needle pierces the insulation, it does not damage it.
 |  |
Please send your ideas, which are very important for our success…