The schematic shown above
represents the circuit that has been used in the 50th
Anniversary Radio. This circuit is
basically the same as that used in the Valandy radio kit, shown on the
previous page, and is similar to many CK722 projects from the 1950s and
1960s. The CK722 is used as an audio amplifier and works best with a high
impedance earphone (2K ohm). Station selection is accomplished by the
parallel combination of the 365mmfd variable capacitor and the variable
inductor “loopstick”. The CK705
germanium diode provides detection of the radio signal and the audio
component is coupled by the .02mfd capacitor to the base lead of the CK722,
which amplifies the signal in a common emitter circuit and directly drives
the earphone.
50th
Anniversary CK722 Radio
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