This small audio amplifier circuit in complementary symmetry was found in the 1974 Mullard Databook. The output pair can also be the BD135 and 136.
This encrypted key was found in a 1989 documentation. It controls a relay that is activated only...
This circuit is from an American transistor book from the 60's. The transistor is germanium of the...
This simple SCR alarm circuit was found in an old Poptronics, but can be easily assembled as all...