Using the integrated circuit 723 we found this power supply in an article in the magazine Radio Electronics from August 1971. The transistor may be a BD136 equipped with a heat sink.
This oscillator was found in a 1976 documentation. The no specified components indicate circuit...
This circuit activates a buzzer when the voltage applied to the input falls below a preset value in...
This protector was found in an Electronics Now from the 90s. The 250 V transient suppressors are common...