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 circuit is from a 1966 General Electric documentation. The circuit applies to sensitive SCRs for...
In the figure a circuit that is the basic application of NE567 for the detection of a tone applied to...
Found in old documentation, this circuit is the receiver for the previous circuit. Components are...