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, obtained in an old publication, causes a second telephone bell to be played in a...
This circuit is an alternative version of the previous one also found in the July 1995 Electronics Now...
This circuit is from 1994, from a technical documentation from National Semiconductor, but can be...