Current indicator (CB22132E)

In this circuit the voltage across the LED is limited by the diodes. The maximum current also depends on the resistor.

Colpitts Oscillator with MOSFET (CB8141E)
Found in an American documentation from 1969, this circuit operates at a frequency determined by the...
Negative ion generator (CB20683E)
This circuit was found in Radio Electronics from the 90s. The components used are common, and the...
Gun Sounds Generator (CB4626E)
The UM3562 integrated circuit is a dedicated circuit found in many toys because it generates three types...