Found in documentation from the 1980s, this circuit uses an operational amplifier from that time. Transistors are also from the era, and general-purpose equivalents can now be used.
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...