This nice analog indicator circuit was found in the January 1974 issue of Radio Electronics magazine. The circuit has 8 scales with individual adjustments. The instrument is rated at 50 uA.
This circuit for a 455 kHz ceramic filter was found in the October 1952 Radio Electronics...
This circuit was found in a Poptronics of the 90's. It can be powered by voltages between 6 and 15...
The microphone of this short-range MW transmitter should be low impedance magnetic (a small...