Basic question 12v

Hi, I have basic knowlege in electicity. I bought a adaptor that clips on a 18v milwakee tool battery that as a port that delivers 12v. The thing is that if i test it , I get 4.4v , but if i touch both polarity it jumps ton 12,3v ,I can let go , it stays at 12.3v. Same with a led strip, plug, nothing, but when I touch both polarity it light up and stay light even when im not touching anything. Either there is something I dont know ( very possible) or the adaptor is not working correctly. I dont really know where to get help, everything is closed where i live. Sorry english is not my first language, hope im clear in my description. Thanks Pascal

by eltarkus
January 13, 2021

I will take a guess and say that there is some smarts built into the adapter that turns on full voltage only after it gets a bit of current at 4.4v. Only guessing

by Foxx
January 15, 2021

There is something not really making sense to me. You say that "but when I touch both polarities", that implies that, before, you didn't ? Then, how do you test 4.4v just touching ... ONE ... polarity (one pole, I assume)? A VOLTAGE is ALWAYS a difference of electrical tension between two points. If you use a voltmeter, one probe on a pole an the other probe hanging in air, you are measuring who knows what. Note that maybe it is just me who does not understand what is evident, though.

by vanderghast
6 days, 16 hours ago
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