42 kHz oscillator (CB21805E)

This circuit was used as an eraser for old tape recorders. The circuit is from a 1960 Mullard transistor manual.

Insect Repellent (CB17682E)
The proposed circuit generates signals in the range between 9 kHz and more than 44 kHz, which, it is...
Integrated FM Radio (CB14571E)
This circuit uses currently uncommon components, including the 10.7 MHz (FI) filter. This circuit was...
Mini Power Supply (CB1411E )
This small power supply for low currents (5mA) is suitable for power low-power TTL experimental circuits....