Using the CMOS IC 4046 we found this VCO in the November 1984 Radio Electronics magazine. The center frequency is given by the capacitor. The maximum frequency is around a few megahertz.
With a coil formed by 7 turns of 26 AWG wire this circuit operates in the 27 MHz range. But you...
The circuit shown is a commercial electronic voltmeter sold in Japan in the 1960s. The circuit is fully...
This amplifier for recording heads was found in a Radio Electronics from September 1963. The...