Found in an American publication of 1968, this circuit makes use of a pilot light of the time. It can be replaced with LED with appropriate series resistor. Transistors may be modern equivalents.
This circuit that simulates the sound of a drum is part of an article published in the Radio...
This circuit was obtained from an Application Note from Linear Technology that manufactures the used...
This is a well-known RC oscillator configuration using a 741 operational amplifier. The circuit is from...