# Measuring change in magnitude of electric current due to change in conducting material characteristics

I am new to this community and hence may not be aware of all the rules. Please do let me know if you think I am violating any. I will try to get it corrected.

I am trying to get an answer to the following questions: 1. What is the order of magnitude of change in electric current when the diameter of the conducting material changes by a few nano meters, like in a chip? I am thinking that it would be of the order of tens of nano amperes. Is that correct?

1. What is the easiest way (circuitry) to measure the change in electric current due to change in conducting material? I would like to measure the change NOT necessarily the original current flowing.

Look forward to your thoughts

Kind regards Shantanu

## 1 Answer

What is the order of magnitude of change in electric current when the diameter of the conducting material changes by a few nano meters

It's going to depend a lot on what was the original diameter of the conductor. If it was a few mm, then a 10 nm change won't make any appreciable difference. If it was 100 nm, it will probably be measurable.

It also depends how you're generating the current. Is it with a constant voltage source or a constant current source, or something in between?

What is the easiest way (circuitry) to measure the change in electric current due to change in conducting material?

The easiest way will be to measure the current with the first configuration, then measure it with the second configuration, then compare the two numbers.

A circuit to measure a current is called an ammeter. If you need to measure a very small current, it might be called a picoammeter.

How you connect the ammeter to the sample to measure it will depend a great deal on the physical configuration of the sample.

• Thanks for your reply... this is definitely useful... the original diameter of conductor would be in tens of nano meters and the variation would be a few nano meters. Also, I would expect a constant voltage source as that is more commonly used in ICs. I would like to measure it using a circuitry as that would have to be done while normal operation of the IC where introduction of an picoammeter might not be possible. Maybe, I need the circuitry of a picoammeter that I can place in the circuit. – Shantanu Oct 3 '18 at 1:09