Found in a 1970 EEE, this circuit generates signals that depend on the C1 capacitor. Transistors are general-purpose types.
Found in Radio Electronics from the 90s, this circuit uses a 741 and can be changed to other...
With a light pulse on the Q1 sensor the circuit turns on and locks. To switch off, a light pulse...
This 10-minute timer was found in the July 1994 Radio Electronics magazine. The relay must be...