This circuit uses an HA2400 consisting of 4 digitally controlled operational amplifiers. The circuit is from a Radio Electronics magazine from March 1980. The power supply must be symmetrical.
We found this circuit in the April 1988 issue of Radio Electronics magazine. The circuit can be...
Relays up to 100 mA can be driven by the 555 with the recommended circuit. The circuit is from an...
This version of the previous circuit, also from Radio Electronics magazine of July 1970, uses R4...