This circuit is from an old American documentation from the 70s. Transistor 2N3904 can be replaced by BC548. The relay must have 100 mA of maximum current.
This circuit, from an old Argentine publication, provides 6 W of output from an output of less...
Found in a documentation from the 90's, this circuit uses only one integrated circuit. The...
We found this circuit in documentation from the 1970s; The circuit uses Japanese transistors of...