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 circuit is from a 1979 publication. The sensor consists of plates or screens that, when...
The circuit is from a Radio Electronics from August 1989. The cells used at that time did not have...
The automatic modulated siren circuit shown in the figure really produces an interesting sound...