We found this circuit in the magazine Eletcronics Now of July 1994. The power supply is according to the relay and the transistor can be any general purpose one.
We found this circuit in a 1976 documentation. The FET can be the BF245 and the bipolar transistor a...
This circuit is the receiver for the CB13997E. The transistor can be the BC548. We also found this...
We found this oscillator in a publication for radio amateurs from the 70s. The circuit generates...