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DiscoverCircuits.com -- Hobby Corner
"Hobby Circuits for
your Hobby Projects"
Last Updated on:
06/19/2009 02:53:12 PM
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Check Engine Beeper Circuit
designed by David Johnson, P.E. |
| When driving down a busy road, you may not
notice a “check engine” indicator light that suddenly turns on within the car’s
instrument panel. You could drive for many miles before noticing the light.
To provide an audible indication of trouble, the hobby circuit below could be added.
When connected to a typical automotive check engine indicator light on the instrument
panel, this circuit will sound a loud beeper, when the light turns on. the hobby
circuit counts on the fact that most check engine signals swing from chassis ground
potential to +12v. When the signal is at 12v it turns on, the n-channel FET which
activates the beeper. |
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Click on Schematic below to view PDF
version of this Circuit |
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