This circuit detects changes in the active cycle of the input signal. The circuit was obtained in a 1966 EEE. Transistors are general purpose types of the time.
This simple metronome, from 1985 documentation uses only transistors and has two settings. For...
We found this circuit in a 1988 documentation. The circuit uses a conventional complementary...
This circuit was found in a 1990 publication. The sensors are electrodes placed in the water tank...