This circuit was found in an ancient American documentation. The power supply is not given, but we have the voltages used. The relay is sensitive type for high voltage.
This circuit was found in a 1977 documentation. With it we have the direct indication, through LEDs...
This circuit provides two outputs of the same signal. One with the original phase and the other...
This circuit was found in a Popular Electronics from the 90s. The circuit uses a general purpose...