This low frequency oscillator circuit was found in an Electronic Design from the 90s. The transistors are common types, and the frequency is given by the crystal.
This is the traditional configuration of na Astable Multivibrator using two NPN ttransistor....
This treble and bass control drains some milliamperes from a 12 V supply and can be used with any...
This is a very simple configuration with a power transistor to control a DC motor from 3 to 12 V...