This sensitive 4-tube, battery-powered receiver was found in a 1949 Radio Electronics. The circuitry was wired in crystal earphones.
We found this circuit in a 1975 radio amateur documentation. The circuit uses TTL technology and...
We found this circuit in an American 1980s documentation. The circuit can be assembled with modern...
This circuit, calibrated to the degree Celsius scale, was found in a National Semiconductor...