This commercial transistor tester circuit (EICO 666) is from a Japanese publication from the 1960s. The switch selects the types of test with the switching of the terminals and the gain ranges.
This circuit is from Signetics' 80s documentation. The circuit generates 100 kHz signals according...
This circuit was found in a Motorola documentation from the 90s. The transistor used is uncommon...
This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...