This circuit was found in Radio Electronics from the 90s. The sensor is an oscillator whose frequency depends on humidity, an uncommon component nowadays.
This circuit, which operates between 7 and 30 MHz, was found in Radio Electronics from the 1980s....
This circuit was found in an old American magazine for radio amateurs. The circuit is based on a...
This low current circuit allows the regulation of voltages in the range of 0.5 to 30 V. We find it...