Easy-peasy extension lead tester

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Phil_G
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Easy-peasy extension lead tester

Post by Phil_G »

This has to be the simplest 'tester' ever and takes just a few minutes to make :D
You'll need to snip a known-good 'universal' extension-lead, then find another battery socket from your junk drawer... and a 5 volt buzzer.
This has to be a DC buzzer, not a piezo sounder. Piezo sounders need an external signal to drive them, more like a speaker. DC buzzers are very cheap off ebay. Then just copy the wiring in the photo. Note that the buzzer has pos & neg pins marked Image

The first check of a new extension-lead has to be by eye of course, ie that the neg, pos & signal are in the right order - black, red, white for Futaba or brown, red, orange if you're a JR/Spektrum user. As we've seen, a few leads have arrived with their wires reversed!

Once we've checked that the wires at both ends are in the right order, then we can try it on the 'tester' :D
What it does is to check for end to end conductivity of the plug, the socket and each of the 3 wires. Beep is good :) Silence is bad! :(
You can check for intermittent faults by jiggling & pulling the extension whilst its under test, making sure the beep doesnt get interrupted.

I've shown it with all the joints exposed - of course you'd insulate them with heatshrink.
You could make a boxed version, even have an internal battery (say 3x AA cells) which would last forever, and of course theres no need for a switch.

Cheers
Phil

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