This 1000: 1 voltage-controlled filter circuit was found in an Electronics Today International in a 1980s edition. The circuit is based on components of the time.
Circuits similar to this appear elsewhere in this section. The transistors can be BC549 (low...
September 2017 - Vishay Siliconix SQ MOSFETs for automotive use are in stock for immediate...
In this circuit we show how to modulate the pulses produced by a 555 in frequency. The circuit can be...