How to detect presence of electricity?

Question

Are there any instruments for that?

i am looking for an instrument that does not need batteries but uses the power from the socket i am testing.

Answer 1

There are hand-held static meters available that detect static charges from a distance (up to several feet away).

To detect AC currents, there are also non-contact meters that sense the magnetic fields of the AC currents flowing in wires. These meters must be held close to the wires to sense the current.

Voltmeters and ammeters measure voltage and current by contact with the circuit you want to detect.
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Answer 2

A volt meter. You can find them at a hardware store.