This circuit was obtained in a QST magazine from the 90s. The circuit makes use of components that are uncommon today. The circuit includes a gain selection switch.
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...