Custom tool for intermittent problem

[Rollinselectrics]

Seems like it should be simple but maybe I’m overthinking it. I bought a 12volt dc counter that has a ground wire and a power wire and it counts every time it receives power. I’m wanting it to only power on with 12 volts but currently down to 7 volts powers it on. I’m trying to keep it very simple and compact and not use relays and such. Any ideas? Thinking maybe just resisters? How would I know what resistance I need?

 

[FrancSevin]

Not enough info here to help.
Sounds like a simple photo eye, or even a dry contact micro switch would do it.
What are you counting???

 

[Rollinselectrics]

Want to leave it on various car circuits to detect intermittent problems where the circuit may get powered on when it should be asleep or lose power when it should be awake.

 

[FrancSevin]

Just wire it in parallel with the device. Red lead to the hot terminal of that device and black to ground
When the device circuit is activated, the counter should click once until it goes off

 

[tommu56]

so you want not count if voltage is 7 volts but count if its 12 volts correct?

use a zener diode wired to stop the flow unless it brakes down and conducts over say 11.5 volts you do need to figure the current for it to work properly and to size it. sorta like MTE 5125A

diode chart

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