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.
Found in a 73 magazine for radio amateurs of the 1980s, this circuit uses a dual-gate MOSFET. This...
This circuit is intended for communications receivers. We can find it in a documentation from the...
This traditional TTL configuration was obtained in a 1977 documentation. The supply must be made...