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.
The circuit is from an old documentation making use of an operational amplifier of the time. The...
We found this circuit in a 1977 CMOS oscillators documentation. The power can be sourced with...
We found this circuit in an old Radio Electronics. Components can be replaced by modern...