Found in an 1868 Mullard documentation this circuit has a dynamic range of 10 Hz to 25,000 Hz. Modern equivalent transistors can be used.
C The combination of rectangular signals of different frequencies and intensities can result in...
We present the circuit of the commercial transistor tester Sanwa SC2 sold in Japan in the 1960s. The...
Although it was found in a British magazine 1976, this circuit can be easily upgraded with the...