This third-order Butterworth filter was found in American documentation from the 1980s. Formulas for component calculations are attached to the diagram.
The integrated circuit used in this filter is not very common today, but the reader can use...
This circuit generates sinusoidal and cosine signals of 2 kHz given basically by the values of C1...
This small FM transmitter, with a few tens of meters in range, is powered by a 9 V battery. The...