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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Friday, December 29, 2017 05:52 AM
Hobby Circuits List
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Indicator Circuits
Automotive Circuits |
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Automotive 12v Electrical System
Voltage Indicator
designed by David Johnson, P.E. |
| When troubleshooting the
12v electrical system of an automobile, it is nice to have a simple voltage
indicator tool instead of a voltmeter. This electronic circuit, hobby circuit
is powered by two AA or even two N cells, which will provide enough energy for years
of service. The circuit has only two leads. |
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One lead connects to the chassis ground of the car.
The second lead can be sharp tip probe. The circuit will indicate if an automotive
electrical circuit has zero volts or 12 volts present. If the voltage is near +12v,
a green LED will turn on. If the voltage is near chassis ground a red LED will
turn on. If the circuit is open, neither light will light. The circuit draws
so little current in the open standby mode that no on/off switch is required.
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Click on Drawing Below to view PDF version of Schematic |
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Indicator
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eMail David A.
Johnson, P.E. about this circuit |
