This sensitive 4-tube, battery-powered receiver was found in a 1949 Radio Electronics. The circuitry was wired in crystal earphones.
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...