This variable filter circuit was found in July 1975 Radio Electronics magazine. The circuit uses 3 general purpose op-amps like the 741 and must use a symmetrical source.
This circuit was obtained from an old publication from 1974 but can still be assembled with some...
This level matrix display was found in a 1994 documentation, but it can still be assembled, as the...
This circuit can be implemented with any triac of the TIC series and the lamp must be...