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.
Found in a Popular Electronics from the 90s, this circuit operates up to about 5 MHz input....
This circuit was found in a 1987 edition of the United States' Hands-On Electronics magazine. The...
This circuit that uses potentiometer tuning, was found in a documentation from the 80's. The...