This circuit detects when a powered circuit suffers a malfunction, lighting an LED. The supply voltage can be changed according to the monitored load.
This pocket-sized VHF receiver was found in Radio Electronics magazine from January 1961. It uses...
Found in 1980s documentation, this oscillator uses an integrated TTL Schottly. The supply must be...
The transistors of this circuit may be the BC548 or BC549 and its power supply can be performed...