This 1 kHz filter was found in the March 1997 issue of Electronics Now magazine. The circuit is applicable to any operational amplifier with a dual power source.
This simple musical instrument was obtained from a 1967 magazine. If the original transistors are...
The transistor of this circuit can be the BC558. The circuit is from an old documentation...
We found this circuit in an old American documentation for hams. The circuit serves as a telegraph...