Which one will work

[Daitey]

Hi Everyone,
Just joined.Well, the issue is i am taking on a project that will require detection of very small changes in currents(an order of micoamperes) and make decisions depending on the magnitude of change.I am thinking of using the ADC(analog-to-digital) of a PIC to detect the magnitude of change.Is there a device i can use for this or is my idea the best option?
Thank you

 

[JimB]

Vital information missing.

You are looking for changes of a few microamps, but is that a change from 10uA to 11uA, or a change from 1.000000A to 1.000001A ?
Both represent a change of 1uA, but the first case is easy, the second maybe needs a bit of thinking about.

JimB

 

[Daitey]

Change of microamps

Thanks.But can you help me figure out the second change that is of a higher precision?Even if i don't use it now its no harm exercising the brain.

 

[Boncuk]

Current changes have to be converted to an equivalent voltage before converting A/D.

For instance using a standard 500Ω burden resistor the voltage across it is calculated according to Ohm's law.

10µA would result in a voltage of 500mV, while 1.000001A would result in 500.0005V.

I wouldn't think an MCU can convert this to digital.

 

[Daitey]

If i am getting you right, do you mean the MCU i plan using (8 bit) cannot do the job?If yes then how do you suggest i continue(move on)?

 

[JimB]

how do you suggest i continue(move on)?

You could start by answering my initial question, you are looking for changes of a few uA, but how much of a change in current do these few uA represent?

JimB