Audio control unit (T377E)

This multi-input tone control and preamplifier was found in the 1961 RCA tube manual. The circuit is recommended for high-fidelity tube amplifiers.

Compact Multimeter (CB3871E)
The accuracy of this multimeter depends on the accuracy of the used resistors. The circuit uses a...
Transformerless Power Supply (CB516E)
The output voltage depends on the zener diode. Zener in the range between 1.2 to 12 V rated to 1 W...
LED Flasher Using in Unijunction Transistor (CB531E)
This circuit produces low power flashes in a LED. Frequency is adjusted by P1 and depends also on...