The circuit selected is from the 1960 Mullard transistor reference manual. The circuit is powered by a single 1.3 V battery and the transistors are germanium.
We found this circuit in an English documentation from 1979. It shows how you use a 100 uA...
This circuit for high-impedance magnetic headphones was suggested as an experimental amplifier for hearing...
This circuit was found in a 1987 publication. A 4017 sequentially counts time in steps set by...