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Active Filter Circuits
Last Updated on: Wednesday, June 02, 2021 01:44 PM

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

Circuits Designed by Dave Johnson, P.E. :

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


Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:

Galaxy Noise Filter  -  Schematic Only__ CB World Informer

Generate CID/CIDCW Analog Signals  -  12/07/00 EDN Design Ideas:  A high-speed mP and active lowpass filters can generate CiD (caller-iD]and CiDCW (caller-iD-on-callwaiting] analog signals (Figure 1).  CiD data transmits at 1200 baud FSK between the first and second 20-Hz ring of an incoming call.  CiDCW uses a CAS (CPE Alert Signal]dual tone, PDF contains multiple circuits, scroll to find this circuit.    Design by Hans Krobath, EEC, Nesconset, NY

High Dynamic Range Bandpass Filters for Communications  -  DN37 Design Notes__ Linear Technology/Analog Devices

High Linearity Components Simplify Direct Conversion Receiver Designs  -  LT5575 Demodulator with 20MHz Low pass Filter, common mode output voltage can be set regardless of input voltage.  A filter at the output of the demodulator filters out of band signal and the filter at the inputs of the ADC performs the antI aliasing function.  __ Linear Technology/Analog Devices App Note, Jul 2, 2012

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 11, 2002

Highpass filters use Modified equal-element Design  -  05/24/01 EDN Design Ideas:  in the circuit of Figure 1 , assume that a brush-type dc motor must drive a load back and forth between two endpoints on a lead screw.  Optical sensors determine end of travel, and an SPDT switch selects to which end to send the l Design by Richard Kurzrok, Queens Village, NY

High-Q 60-Hertz Notch Filter  -  This high-Q notch filter is based on the "Twin-T" design.  It produces a very deep notch in the response curve at about 59.7 Hz. This is useful to remove 60-Hz hum and noise from audio recordings or live performances. Response is down over -60db at the center point.
 __ Designed by Len Galasso

Improve roll-off of Sallen-Key filter  -  09/30/04 EDN Design Ideas:  The well-documented Sallen-Key active filter is a staple of analog design.  This design idea shows a way to obtain better roll-off by adding just a few common passive components.  Figure 1a   Page includes several designs.  Scroll to find this one Design by Doug Glenn, Teledyne, Lewisburg, TN

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

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

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

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

LC filter Design on-line calculator  -  This is an interactive design package for designing analogue (i.  e.  hardware) filters made of inductors and capacitors (Ls and Cs).  Fill in the form and press the ``Submit'' button, and a filter will be designed for you.   __ Designed by Tony Fisher

Linkwitz Cosine Burst Generator  -  Based on work done by Siegfried Linkwitz (reproduced with his permission)  __ Designed by Rod Elliott  ESP

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 10, 2000

Low Pass Filter for FM 88-108 MHz  -  Filter used for eliminate unwanted harmonic frequency at second and third.  Notch filter, Band Pass Filter (BPF) , and High Pass Filter (HPF) sometime combined in constructing LPF design.  Schematic below for FM Broadcast Lowpass Filter 88-108 MHz__ 

Low pass filter for subwoofer  -  The acoustic spectrum is extended by very low frequencies 20iz and reaches as the 20000iz in high frequencies.  In the low frequencies is degraded the sense of direction.  This reason us leads to the utilization speaker for the attribution of very low frequencies.  The manufacture that to you we propose distinguishes these frequencies, in order to him we lead to the corresponding amplifier.  The acoustic filters are met in various points in the sound systems.  __ 

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 04, 2000

Low pass filter-subwoofer filter  -  The acoustic spectrum is extended by very low frequencies 20iz and reaches as the 20000iz in high frequencies.  In the low frequencies is degraded the sense of direction.  This reason us leads to the utilization speaker for the attribution of very low frequencies.  The manufacture that to you we propose distinguishes these frequencies, in order to him we lead to the corresponding amplifier.  The acoustic filters are met in various points in the sound systems.   __ Designed by Steve Filianos

Lowpass Filter Discriminates Step Input From Noise  -  18-Sep-03 EDN Design Ideas:  Numerous applications exist in industry, particularly with control systems, in which it is desirable to remove all but the lowest frequency components from a signal to effectively yield a dc voltage.  This voltage may, for example, serve as a setpoint to a PiD controller in a process-control or an HVAC application, in which the cable that is carrying the analog signal is exposed to a wide spectr Design by Eric Desrochers, Aircuity Inc, Newton, MA

Lowpass filter has improved step response  -  19-Feb-04 EDN Design Ideas:  A common problem that arises when you design lowpass filters for signal conditioning is the filters' effect on the system's time-domain response.  Because pushing the cutoff frequency lower slows the step response, the system may fail to recognize significant changes within a reasonable amount of time Design by John Guy and Robert Nicoletti, Maxim Integrated Products, Sunnyvale, CA

Low-Pass Filter RFI Filter  -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

Lowpass filter uses only two values  -  5-Jul-01 EDN Design Ideas:  in recent years, image-parameter design of LC filters has received new consideration (references 1 and 2].  The composite lowpass filter uses interior constant-k full sections terminated by m-derived half-sections.  For best paSSBand response, you usually select m to equal 0.6.  However, m=0.5 can still give useful filter performance while reducing the number of component values Design by Richard M Kurzrok, Queens Village, NY

Lowpass, 30-kHz Bessel filter offers high performance for audio applications  -  Thanks to its property of applying an equal amount of delay to all frequencies below its cutoff frequency, the Bessel linear-phase filter sees service in audio applications in whichThanks to its property of applying an equal amount of delay to all frequencies below its cutoff frequency, the Bessel linear-phase filter sees service in audio applications in which Design by Troy Murphy, Analog Devices, San Jose, CA; Edited by Brad Thompson and Fran Granville - February 16, 2006

LTC1560-1: Tiny 1MHz Lowpass Filter uses No Inductors  -  DN169 Design Notes__ Linear Technology/Analog Devices

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


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