This circuit has a normally low output that is triggered by a high pulse. The circuit is from Radio Electronics from November 1984. The frequency is given by C1.
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...