hi
fraid so, this time i may be trying to do the impossible,
im looking or a way of detecting the presence of current through a wire .
but, and its a big but, it must be completely non invasive,
the current is around 6 amps,and the voltage 12 volt dc.
i dont need to measure the current, just wether it present or not.
i am getting a few - about 6- degrees deflection on a cheap compass,
not very practical though.
could use a small coil if it was split, but i suppose that defeats the object of a coil,
any and all ideas welcome
thank you
doug

 

Epoxy a thermistor to the wire and see if you can detect a temperature rise?

 

Hello Tibbles

The DC clamp-on current meter. uses a coil to measure DC Current.
The secret is that circulate AC signal through the coil which is wound on a ferrite core.
As soon as a DC current to flow. alter the flow of AC current; this change is converted to a measure that could be displayed on a galvanometer or a digital display.

Another method is to use a device known as Hall effect.

https://in.answers.yahoo.com/question/index?qid=20100829100831AADwPk9
ISHWAR Answer, 4 years ago, in YAHOO

The Hall effect type digital clamp meter is able to measure both DC and AC
The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current. The Hall coefficient is defined as the ratio of the induced electric field to the product of the current density and the applied magnetic field. It is a characteristic of the material from which the conductor is made, as its value depends on the type, number, and properties of the charge carriers that constitute the current.

You can get the ferrite core from an old PC power supply.
The Hall effect device must investigate the price of it.

 

I recommend a current transformer or a hall effect sensor like MrCarlos suggested.