This amplifier for electrometer can work with currents of 0.1 pA in a band of 1 Hz. The circuit is from NASA in a publication of the 60s. Transistors are general purpose types.
This amplifier was suggested by the Texas Instruments linear applications manual of the 90s....
In the figure we have an infrared receiver circuit using an operational 741. The circuit is an...
This circuit is from 1968 documentation. We can assemble it with more modern components such as a...