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.
This circuit can be used as a shield for transmitting the temperature of a sensor. The circuit is from...
We found this circuit in an old manual. The bypass range is 20 MHz and the power supply must be...
This small audio amplifier uses germanium transistors and a 12 V supply. The circuit is from a...