We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply need not be symmetrical. The FET in the feedback acts as an automatic gain control.
This latched alarm uses a double relay for this purpose and can control higher power external...
This circuit was found in an old American documentation on telecommunications. It is suitable for...
Taking advantage of the comparator setting, we can use the Norton amplifier as an over temperature...