Electronic filters is a linear two-port device designed to transmit spectral components of the input quantity according to a specified law, generally in order to pass the components in certain frequency bands and to attenuate those in other bands.
| Symbol | Description |
|---|---|
 | Name: Filter, general symbol Source: IEC 60617-2019, ANSI/IEEE Std 315A-1986 |
 | Name: High-pass filter1) Source: IEC 60617-2019, ANSI/IEEE Std 315A-1986 |
 | Name: Low-pass filter2) Source: IEC 60617-2019, ANSI/IEEE Std 315A-1986 |
 | Name: Band-pass filter3) Alternative name: Frequency filter (bandpass) Source: IEC 60617-2019, ANSI/IEEE Std 315A-1986, IEEE Std 315-1993 |
 | Name: Band-stop filter4) Source: IEC 60617-2019, ANSI/IEEE Std 315A-1986 |
 | Name: Band-pass filter switched by gas discharge Source: IEC 60617-2019, ANSI/IEEE Std 315A-1986 |
 | Name: Mode filter Source: IEC 60617-2019, ANSI/IEEE Std 315A-1986 Remark: The asterisk shall be replaced by the indication of the mode suppressed. |
 | Name: Surface acoustic wave (SAW) filter Source: IEC 60617-2019 |
 | Name: Band-pass filter with variable pass-band; selectivity control Source: IEC 60417-2020 |
 | Name: Band-pass filter with variable centre frequency Source: IEC 60417-2020 |
 | Name: Variable band-stop filter Source: IEC 60417-2020 |
Notes
For convenience, I give definitions of the different types of filters:
- High-pass filter is a filter having a single pass band above a cut-off frequency and a stop band for lower frequencies (IEC 60050-561-2014).
- Low-pass filter is a filter having a single pass band below a cut-off frequency and a stop band for higher frequencies (IEC 60050-561-2014).
- Band-pass filter is a filter having a single pass band between two specified stop bands (IEC 60050-561-2014).
- Band-stop filter is a filter having a single stop band between two specified pass bands (IEC 60050-561-2014).
