Small/Cheap Galvanometer Needed

[Physicist]

Main Question or Discussion Point

Hello,

I'm doing an experiment and need a small and cheap galvanometer. Does anyone know where can I find it?

Regards

 

[The Electrician]

What do you actually need to measure? A small current or a small voltage? What magnitude?

Does the instrument need to be a ballistic galvanometer, or would a short time constant be ok?

 

[Physicist]

A need to detect small currents and indicating the direction of them.

Any galvanometer would be ok.

 

[The Electrician]

How small? A milliampere? A microampere? A nanoampere? A picoampere?

 

[Physicist]

I meant small = small in size (not the range).

 

[The Electrician]

You said "A need to detect small currents and indicating the direction of them."

That's "small currents", which has nothing to do with the physical size of the instrument.

How small are the currents you need to detect?

 

[Physicist]

microamps or even milliamps would be OK as I can vary the other components.

 

[The Electrician]

I see some fairly low cost items here:

http://shop.ebay.com/?_from=R40&_trksid=m38&_nkw=galvanometer&_sacat=See-All-Categories

You could also use a zero center panel meter for the purpose:

http://shop.ebay.com/items/?_nkw=panel+meter+50-0-50&_sacat=0&_trksid=m270&_odkw=panel+meter+zero+center&_osacat=0

http://cgi.ebay.com/127HR-100-0-100-Panel-Meter-QTY-1-ea-L2_W0QQitemZ190275344845QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2c4d4b59cd