Measure direction of subpicoamp current

[swooshfactory]

Is it possible to measure the direction of a current at current magnitudes this small? Or only its magnitude?

 

[Carl Pugh]

Measure using what method.
It is possible to measure the direction of currents to ground in the femtoampere range.

 

[f95toli]

There are many commerical instruments that can go well below a pA
See e.g.
http://www.keithley.com/products/dcac/sensitive/lowcurrent/?mn=6485

This is from the point of view of the user no different than using a multimeter.

Note that how well you can do this will depend on the impedance, it is possible to measure very small currents if you somehow can "translate" your current into a voltage via a (large) impedance (but there are limits to how this can be done, e.g. the Johnson noise of the impedance).

 

[jim hardy]

here's some practical information and a device.


http://www.analog.com/library/analogdialogue/bestof/pdf/05_2.pdf

http://www.ti.com/lit/ds/symlink/lmc6001.pdf