Using known tubes, this receiver was found in a Radio Electronics from 1949. The circuit does not include the power supply.
We found this circuit in the June 1991 issue of Radio Electronics magazine. The integrated circuit is...
We found this circuit in a 1991 publication. It indicates when an analog phone line is busy by...
Originally created to feed the filaments of a 12AX7 as an audio preamplifier to eliminate the...