A number of filter circuits and a whole bank of cathode ray tubes.

In some active filter circuits, one parameter can be adjusted without affecting the others.

Both band-pass and band-stop filters can be constructed and some filter circuits are shown later in the article.

The damping of filter circuits is adjusted to result in the required bandwidth.

Sweep generators are commonly used to test the frequency response of electronic filter circuits.

There are many different types of filter circuits, with different responses to changing frequency.

Operating cycle of the filter circuit showing the inductor current waveform.

Alternatively, passive components can be utilised to construct filter circuits before the amplifier.

Third-order acoustic crossovers are often built from first- or second-order filter circuits.

The oscillator output was fed into two parallel resonant filter circuits.