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.
We found this circuit in a 2005 documentation. The circuit uses an infrared piezo sensor...
This circuit was found in a 1995 documentation. It deactivates a power supply in the event of a...
This circuit was found in the September 1993 Electronics Now magazine. It is based on the 555 and...