This high-Q low-pass filter was found in the October 1990 issue of Radio Electronics magazine. The frequency depends on the capacitors used and is on the order of a few tens of hertz.
This circuit was found in an old European documentation. When R2 is cut off the circuit triggers...
This circuit was found in the comparator's own documentation, serving others in the same series. The...
This oscillator uses germanium transistors. It was found in the Radio Electronics magazine of may...