How to tell a wire is plugged in?

[gyrgi]

I need to use a sensor to determine if a wire is turned on without using a voltage or current sensor.

I've been playing with using a capacitance sensor or sending a small signal

 

[jedishrfu]

Welcome to PF!

Is this for homework?

If so what is the full problem description?

Are you trying to detect if the wire is conducting electricity without actually touching it in any way?

 

[russ_watters]

...and if so, are you aware that there are non-contact current sensors?

 

[Svein]

I need to use a sensor to determine if a wire is turned on without using a voltage or current sensor.

What do you mean, "turned on"? If you mean "connected to the power network" the answer is quite different from what you will get if you mean "connected to the phone line".

 

[dlgoff]

And there are commercial circuit tracers available to purchase.

 

[Jeff Rosenbury]

How to tell if there's an electrical connection without using electricity? An interesting question.

Hopefully your practical problem is easier than the theoretical one. There have already been several good suggestions posted that might help.

For the pedantic problem I can only think of making sure there's a good physical connection. Perhaps a spring loaded connector with an actuator/transducer? Maybe some sort of quantum oscillator for measuring tunneling between the two wires without actual electron flow?

 

[jim hardy]

I need to use a sensor to determine if a wire is turned on

?

Just what level of arousal are you hoping to detect ?