Found in a 1924 documentation, this circuit is powered by 3 batteries, two of which are high voltage. The output is a high impedance headphone jack.
This simple 60's receiver is powered by solar cells of the time. The transistor is made of...
This circuit has a duty cycle of 50%. We found it in old English documentation. The center...
The National Semiconductor LM377 integrated circuit consists of a low power audio amplifier. This...