-- jt]]
Hi All,
I want to measure picoampere range currents (on transistor like devices) and would like to have an idea how difficult it is to make a measurement device for this purpose. I have read about the precautions needed for such setups, but not about the actual implementation issues using ICs and components.
Somebody told me that I can make a device like this using a (schematically) simple circuit with INA108 (or similar) precision amplifiers, coupled to a DAQ via a system amplifier. This setup can be tuned to different input ranges by resistances attached to INA108.
Then I came across DDC11X series (e.g. DDC112) from TI, and it seems to be perfect for my purpose.
Could you please tell me the pros and cons of the two approaches. I would also like to know same about making source units using INA108 and REF200 and REF5050 from TI.
thanks a lot, Shishir. ps: I would prefer not to buy a Keithley (say 2400 or 2612) due to budget constraints. Also, the circuits for my range of measurements don't seem overly complex, so I think I can manage.