Bass control (CB8722E)

Found in a 1993 Electronics Hobbyst Handbook, this passive circuit can be used with common preamplifiers and amplifiers.

Crystal Controlled Oscillator (CB6186E)
This circuit is from Signetics' 80s documentation. The circuit generates 100 kHz signals according...
500 MHz Amplifier (CB9178E)
This circuit was found in a Motorola documentation from the 90s. The transistor used is uncommon...
Intermittent buzzer (CB20494E)
This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...