This circuit, which controls both the temperature and the level of a liquid in a reservoir, was found in an Electronic Design from the 90s. The circuit is based on a double 555.
This circuit accelerates the tripping of a relay when energized. The circuit uses the CA3018...
The circuit shown is from the National Semiconductor 1994 Linear Applications Handbook. The base...
This ultra-simple circuit has the frequency determined by the LC network. Any general purpose JFET...