A scheme of simple band-pass RC- and LR- filters on operational amplifiers containing only one capacitor or inductor and 3 resistors is proposed. A comparison is made of the amplitude-frequency ...

For example, a programmable second-order, low-pass Butterworth filter with a corner frequency ranging from 200 Hz to 20 kHz can be designed by setting C1 = 0.022 µF and C2 = 0.1 µF. The values ...

There’s also a low-pass filter that’s controlled by a couple of light-dependent resistors, which can be played by blocking them off with a fingertip.

A subsonic filter is mostly used in low frequency technology. Most often, the very low frequencies create distorsions in music recording or reproduction. This happens independent of the applied ...

The audio circuitry from the Raspberry Pi 3. The low-pass filter’s 220R and 100nF now give it a cut-off of just over 7kHz, and the high-pass filter’s 100R and 47uF give it 33Hz.