This 9 W amplifier with transistors from the 60's was found in documentation of the time. The output transistors must be mounted on heat radiators and the power supply is included.
This alarm circuit is from a 1990 Electronics Handbook. Transistor Q1 can be a BD135 and the relay...
This trigger circuit was found in old European documentation, but it can be implemented with...
This circuit is from the SGS Integrated Circuits Manual of 1982. The integrated circuit used is...