This old 1967 audio preamp uses germanium transistors. It was found in Japanese documentation at the time and has a gain of 70 dB, being powered by p V. The input sensitivity is only 12 mV.
This circuit uses a large surface diode to detect radiation (alpha and beta particles, in addition to...
This preamplifier for the phonographic capsule was obtained in an Argentine publication from 1973....
This circuit is from a 1993 publication and can be implemented with any optical isolator that has...