This powerful siren is suitable for warning or alarm systems. The components are current and the transistor 3055 must be mounted on a good heat sink.
This telegraph monitor was found in an American documentation for radio amateurs from the 1970s. The...
We found this circuit in a European publication from the 1970s. The transistor is made of...
This adjustable source from 2 to 15 V uses transistors from the 60's, as indicated in the...