Found in an Australian documentation from 1991, this circuit was sold in a kit at the time. It is a small FM transmitter with a very common configuration, also found in other projects on this site.
We found this antenna amplifier or Booster circuit in an Electronics Now from the 90s. The circuit...
We found this circuit in the Linear Applications Handbook of the 1994 National Semiconductor. The...
This circuit is from a 1976 Motorola power semiconductor manual. In it we have the optical...