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.
The circuit presented is quite simple, employing tone modulation of the signal. To receive the...
This circuit was obtained in a 1967 Raytheon manual. The company's component is an optical coupler with...
This circuit was obtained in an Electronic Engineering of the 90s. The operational amplifiers and...