Tachometer Wiring Questions

I rewired the tach using the wiring setup that FanMan provided and it's working now. For info I searched eBay for LED tachometers and found no less than four different wiring schemes. My tach didn't come with any wiring instructions so it was a guessing game from the start. I'm not complaining as the tach cost me $9 delivered. Just a heads up to anyone buying one.

Thanks FanMan, hman and MKSJ for your help.

Tom S.


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There are many different variants on these tachometers. The older designs connect the NPN sensor power directly to the incoming power plus a trigger line. Most of the newer designs I have seen/use have a separate power input with a wider input voltage range and a separate regulated voltage connection for the NPN sensor. They have a speed range of around 4-99999 RPM. These are usually available through eBay, and maybe a little less confusing to wire.
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Reflective optical sensor is easy too. Just use a piece of silver tape on the pulley. Easier than mounting magnets. TCRT5000 sensor works fine with these tachs, can mount with double side foam tape.
 
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