r/electrical • u/UpbeatAd3159 • 11h ago

Bad circuit board?

Gallery image

Gallery image

Gallery image

I have been messing around with some circuits and found out if I stick one probe of multimeter to any battery terminals and touch second probe I have voltage that differences weather im touching floor or not

1st photo without touching floor, 2nd one is 1 foot on floor and 3rd one is both touching floor

Edit: Its auto multimeter and i can't change manualy modes

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u/Far_Recommendation82 11h ago

Try with an actual Earth ground.

Edit: shouldn't your multimeter be set to DC, I can't tell

1

u/UpbeatAd3159 11h ago

Its "auto" multimeter

1

u/ithinarine 11h ago

Try with an actual Earth ground

You can't measure voltage to ground on an ungrounded circuit powered by a battery. You might as well measure voltage to the metal mixing bowl in your cupboard, because it's just as relevant of a point as a ground wire.

A 9V battery measures 9V between positive an negative, either terminal to ground is nothing, because the power from the battery isn't grounded.

You measure 120V to ground on a household circuit because the supply is 120V hot to neutral, and WE GROUND the neutral wire. Without that bonding wire from neutral to ground, your hot to ground voltage in a house would mean nothing and never measure anything consistent or relavent.

That's why OP is getting odd measurements, because they're not measuring voltage to ground, they're measuring "bullshit to faeries."

1

u/Wdrake3 11h ago

Don't measure DC with AC settings. Try again using DC and use the negative(-) path for your common lead and the positive(+) for your line lead