Found in a Raytheon transistor manual from the 1950s, this circuit uses one of the first commercially available transistors, the CK722. The circuit is for using a small speaker as a microphone.
Found in old documentation, this circuit makes use of amplifiers of the time, uncommon today. Next...
Although quite simple, the usefulness of this circuit is great. It can even mean gains for those...
This circuit converts inductances on two scales into voltages. The circuit was obtained from a...