Active Filter Circuits
#'s - A     B - E     F - L     M - R     S - Z
 

Last Updated: June 02, 2021 01:44 PM

FET Input High Speed Light Detector -  This circuit is yet another design that converts current from a PIN photo diode to a voltage.  It has a bandwidth that extends beyond 50MHz. . . Circuit by David Johnson P.E.-June, 2000

Form Push-Pull Driver using N-Ch & P-Ch Transistors  -  This circuit can produce high speed output signals with fast rise and full times.  The unique change pump action allows the voltage of the upper P-ch device to range from millivolts to hundreds of volts.  The output current is only limited by the rating of . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

High Pass Active Filters -  This is a collection of inverting and non-inverting active high pass filter circuits.  I included one, two three, four and six pole filter circuits.  You can change the component value ratios shown to achieve any frequency cut-off you may need. . . Circuit by Dave Johnson P.E.-February, 2002

High Pass Active Filters -  This is a collection of inverting and non-inverting active high pass filter circuits.  I included one, two three, four and six pole filter circuits.  You can change the component value ratios shown to achieve any frequency cut-off you may need. . . Circuit by Dave Johnson P.E.-February, 2002

High Speed Light Detector from FET Input -  This circuit is yet another design that converts current from a PIN photo diode to a voltage.  It has a bandwidth that extends beyond 50MHz . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Laser Light Detyector-10Mhz to 20Mhz -  This circuit was originally designed to detect laser light pulses for an optical Ethernet communications system.  It has good ambient light immunity . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Low Pass Active Filter Designs -  This is a collection of inverting and non-inverting active low pass filter circuits.  I included one, two three, four and six pole filter circuits.  You can change the component value ratios shown to achieve any frequency cut-off you may need. . . Circuit by David A. Johnson P.E.-December, 2000

Low Pass Active Filter Designs -  This is a collection of inverting and non-inverting active low pass filter circuits.  I included one, two three, four and six pole filter circuits.  You can change the component value ratios shown to achieve any frequency cut-off you may need. . . Circuit by David A. Johnson P.E.-December, 2000

Low Pass Filter, 3Khz, with an Audio Amp -  This circuit uses a switched capacitor filter IC from National Semiconductor to filter signals with frequencies higher than the 3KHz needed for voice audio.  The schematic includes an audio amplifier that is designed to drive a standard audio head phone . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Low Pass Filter, 3Khz, with an Audio Amp -  This circuit uses a switched capacitor filter IC from National Semiconductor to filter signals with frequencies higher than the 3KHz needed for voice audio.  The schematic includes an audio amplifier that is designed to drive a standard audio head phone . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

N-Ch & P-Ch Transistor Form Push-Pull Driver -  This circuit can produce high speed output signals with fast rise and full times.  The unique change pump action allows the voltage of the upper P-ch device to range from millivolts to hundreds of volts.  The output current is only limited by the rating of. . . Circuit by Dave Johnson P.E.-June, 2000

Filter Berka-Herpy (BH) Second Order Highpass non-Inverting  -  Schematic only, no text included__ 

Filter Berka-Herpy (BH) Second Order Lowpass non-Inverting  -  Schematic only, no text included__ 

Filter Berka-Herpy (BH) Second Order Notch non-Inverting  -  Schematic only, no text included__ 

Filter Deliyannis Second Order Bandpass I inverting  -  Schematic only, no text included__ 

Filter First Order Highpass I non-Inverting  -  Schematic only, no text included__ 

Filter First Order Highpass II non-Inverting  -  Schematic only, no text included__ 

Filter First Order Highpass III inverting  -  Schematic only, no text included__ 

Filter First Order Highpass IV inverting  -  Schematic only, no text included__ 

Filter First Order Lowpass I non-Inverting  -  Schematic only, no text included__ 

Filter First Order Lowpass II non-Inverting  -  Schematic only, no text included__ 

Filter First Order Lowpass III inverting  -  Schematic only, no text included__ 

Filter Fliege Second Order Bandpass non-Inverting  -  Schematic only, no text included__ 

Filter Fliege Second Order Highpass non-Inverting  -  Schematic only, no text included__ 

Filter Fliege Second Order Lowpass non-Inverting  -  Schematic only, no text included__ 

Filter Fliege Second Order Notch non-Inverting  -  Schematic only, no text included__ 

Filter KHN (Inverting Input) Second Order Bandpass non-Inverting  -  Schematic only, no text included__ 

Filter KHN (Inverting Input) Second Order Highpass inverting  -  Schematic only, no text included__ 

Filter KHN (Inverting Input) Second Order Lowpass inverting  -  Schematic only, no text included__ 

Filter KHN (Inverting Input) Second Order Notch non-Inverting  -  Schematic only, no text included__ 

Filter KHN (Non-Inverting Input) Second Order Bandpass inverting  -  Schematic only, no text included__ 

Filter KHN (Non-Inverting Input) Second Order Highpass non-Inverting  -  Schematic only, no text included__ 

Filter KHN (Non-Inverting Input) Second Order Lowpass non-Inverting  -  Schematic only, no text included__ 

Filter KHN (Non-Inverting Input) Second Order Notch inverting  -  Schematic only, no text included__ 

Filter Mikhael-Bhattacharyya (MB) Second Order Bandpass non-Inverting  -  Schematic only, no text included__ 

Filter Mikhael-Bhattacharyya (MB) Second Order Highpass non-Inverting  -  Schematic only, no text included__ 

Filter Mikhael-Bhattacharyya (MB) Second Order Lowpass non-Inverting  -  Schematic only, no text included__ 

Filter Mikhael-Bhattacharyya (MB) Second Order Notch non-Inverting  -  Schematic only, no text included__ 

Filter Multiple Feedback (MFB) Second Order Bandpass II inverting  -  Schematic only, no text included__ 

Filter Multiple Feedback (MFB) Second Order Highpass inverting  -  Schematic only, no text included__ 

Filter Multiple Feedback (MFB) Second Order Lowpass I inverting  -  Schematic only, no text included__ 

Filter Multiple Feedback (MFB) Second Order Lowpass II inverting  -  Schematic only, no text included__ 

Filter quashes 60-Hz interference  -  03/21/13  EDN Design Ideas:  9Originally published in the December 19, 1991, EDN-Design ideas) The circuit in Figure 1 filters 60-Hz interference from low-frequency, low-level signals.  The filter exhibits 40-dB rejection (Q=0.75) and draws 95 μA max from a single-sided 5V supply.   Design by Adolfo Garcia

Filter Sallen-Key (SK) Second Order Bandpass non-Inverting  -  Schematic only, no text included__ 

Filter Sallen-Key (SK) Second Order Highpass I non-Inverting  -  Schematic only, no text included__ 

Filter Sallen-Key (SK) Second Order Highpass II non-Inverting  -  Schematic only, no text included__ 

Filter Sallen-Key (SK) Second Order Lowpass I non-Inverting  -  Schematic only, no text included__ 

Filter Sallen-Key (SK) Second Order Lowpass II non-Inverting  -  Schematic only, no text included__ 

Filter Sallen-Key (SK) Second Order Notch non-Inverting  -  Schematic only, no text included__ 

Filter Tow-Thomas (TT) Second Order Bandpass inverting  -  Schematic only, no text included__ 

Filter Tow-Thomas (TT) Second Order Lowpass non-Inverting  -  Schematic only, no text included__ 

Filter Twin-T Second Order Bandpass inverting  -  Schematic only, no text included__ 

Filter Twin-T Second Order Highpass non-Inverting  -  Schematic only, no text included__ 

Filter Twin-T Second Order Lowpass non-Inverting  -  Schematic only, no text included__ 

Filter Twin-T Second Order Notch I non-Inverting  -  Schematic only, no text included__ 

Filter Twin-T Second Order Notch II non-Inverting  -  Schematic only, no text included__ 

Fourth order Butterworth BPF  -  The perfect BPF would have little or no loss within the passband infinite attenuation at all frequencies outside the passband.  Such filters don't exist in the real world.  The designer of a practical filter will always have to make some compromises.  These compromises involve various trade-offs between filter bandwidth, passband loss, stop band attenuation, passband ripple, i/O matching and phase/delay characteristics __ Designed by EI9GQ homebrew radio