Found in a 1964 Electronic Design this circuit makes use of components of the era. The output is 2 V peak to peak and the input is 2 V. The maximum frequency depends on the employed components.
This simple transistor tester circuit was found in the February 1968 issue of Radio Electronics magazine....
A touch of the X1 sensor causes the motor to be activated for a time that can be adjusted in P1....
This is a traditional flasher configuration with two neon lamps. The frequency is given by the 100 nF...