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Control Circuits

 
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Last Updated: October 24, 2017 02:54 PM

Circuits Designed by Dave Johnson, P.E.

 

Advertising Badge #1 with Flashing LEDI have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by David Johnson P.E.-March, 2002

Advertising Badge #2 with Flashing LEDThis circuit uses a CD4013 dual D Flip/Flop IC.  A single lithium battery will provide months of continuous LED flashing.  It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by David A. Johnson P.E.-March, 2002

Alarm Sounds At Freezing TemperaturesThis electronic hobby circuit below is designed to activate a beeper alarm, whenever the outside air temperature is below 0 degrees C   (32F) .  A 9v battery powers the hobby circuit.  The average 9ua current is so low that the battery should last for many years . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Alternating CW & CCW Motor DriverA while back a company needed a motor controller for a custom door latching system.    The system used a small brush motor with a speed reduction gear to both latch and unlatch the door.    When pulsed for about 250ms in the clockwise direction, the motor would unlatch the door. . . Circuit by David Johnson P.E.-September, 2010

Amplifier for a Xenon Lamp Flash Detector  - This circuit has a very low standby current requirement yet has very high sensitivity toward the light flashes from a xenon lamp.  When connected to a flip/flop it can serve as an on on/off Controller. . . Circuit by David A. Johnson P.E.-February, 2002

Audio Activated SwitchThis circuit will activate a transistor switch when it detects at least 50mv peak to peak of an audio signal.    It could be used to turn on a relay, routing the signal to were it is needed.. . . Circuit by Dave Johnson P.E.-July, 2006

Audio Frequency Digital Noise GeneratorWhen you need to test an audio circuit with broadband noise, this circuit works great.  It uses just three inexpensive C-MOS ICs that generate a series of output pulses whose widths vary randomly.  I included a level control pot. . . Circuit by David Johnson P.E.-July, 2000

Automatic DC Motor BrakeIn many DC motor powered systems you would like the motor to quickly come to a full stop.   This circuit provides an automatic electronic braking action to any DC motor ranging from 6v to 24v up to 1 amp of current.  Some of the component values could be changed . . . Hobby Circuit designed by David Johnson P.E.-September, 2004


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

 
 

ADC enables temperature-compensated weigh-scale measurements -  5-Jul-01 EDN-Design Ideas You can provide temperature compensation in weigh-scale applications by simultaneously measuring both the temperature of the bridge and the primary output of the bridge transducer.  Traditionally, an integrated multiplexer connects multiple input variables to a single sigma-delta ADC.  Each time the multiplexer switches the input, the ADC must flush the digital filter of all data pertaining to t __ Circuit Design by Albert O'Grady, Analog Devices, Limerick, Ireland

ADC Helps Temperature-Compensate Transducer -  01/20/94 EDN-Design Ideas You can use many tricks to make temperature-compensated resistive full-bridge transducers, such as piezoresistive pressure or strain-guage sensors.  Most of these tricks use some additional thermosensitive components that produce a compensating voltage or current.  The disadvantages of such solutions are obvious  low accuracy __ Circuit Design by Alexander L Belousov, Science Instruments Co, Baltimore, MD

ADC Source Impedance for Hercules ARM Safety MCUs (Rev. B) -  The brushless DC motor has stator windings and permanent magnets on the rotor.  The windings are connected to the control electronics and there are no brushes and commutators inside the motor.  The electronics energize the proper windings similar to a commutator; the windings are energized in a moving pattern that rotates around the stator.  The energized stator windings lead the rotor magnet.   __ Designed by Texas Instruments App Notes, 6-Sep-11

Add a manual reset to a standard three-pin-reset supervisor -  12-Apr-07 EDN-Design Ideas Simply adding a couple of resistors, a capacitor, and a pushbutton switch transforms a standard three-pin-reset supervisor into a manual reset __ Circuit Design by Derek Vanditmars, Delta Controls, Surrey, BC, Canada

Add a Schmitt-trigger function to CPLDs, FPGAs & applications -  10/13/05 EDN-Design Ideas For slow-slewing signals, hysteresis solves trigger problem __ Circuit Design by Stephan Roche, Santa Rosa, CA

Add ethernet connectivity your projects -  The kit contains a development board with a 32-bit MIPS4k PIC32 microcontroller, a 10/100 Ethernet port, an on-board debugger and programmer, and an OTG USB port.  You can get the User's Guide and code examples from the Microchip ESK page.  Microchip has a software library collection for their line of PIC16/PIC18/PIC24/PIC32 microcontrollers called "Microchip Application Libraries" or MAL.  This collection includes the TCP/IP stack the kit uses. __ Designed by Peter Jakab

Add Extra Output to a Boost Converter -  11/17/11  EDN-Design Ideas Designers use step-up-converter ICs in battery-powered portable equipment.  These chips usually provide one output with a fixed or an adjustable voltage.  Some chips contain an LBI/LBO   (low-battery-in/low-battery-out) function.  The chip manufacturer intends __ Circuit Design by Vladimir Oleynik, Moscow, Russia

Add phases to Simple Circuit RC oscillator -  08/25/14  EDN-Design Ideas Demonstrates a simple way to generate a multiphase clock signal, the frequency of which can be varied with minimal change in phase shift  (s).  The phase shift of the second output can be tuned from near zero to 180° without affecting the frequency.  The basic circuit uses a minimum of parts: one cap, two resistors, plus two Schmitt triggers.   __ Circuit Design by Einar Abell

Add Sequencing & Shutdown Control to Regulator -  10/30/03  EDN-Design Ideas Modern microprocessor- or FP-GA-based circuits require separate and independent power-supply voltages for the core and the I/O circuits.  Some devices require stringent control of the turn-on characteristics and sequencing of these  __ Circuit Design by Said Jackson, Equator Technologies Inc, Campbell, CA

Add voice command to virtual instrumentation -  05/30/02 EDN-Design Ideas Debates still persist in the engineering community about the relative merits of analog and digital controls of instrumentation.  Meanwhile, a revolutionary new type of control—voice-command control—is gaining acceptance in many application areas  (Reference 1].  This design idea focuses on the practical implementation of the Voice Commander voice-command interface in a virtual-instrume __ Circuit Design by Alexander Bell, Infosoft International Inc, Rego Park, NY

Add voice commands to your CAD systE - M -  05/02/02 EDN-Design Ideas The first time I activated the Language Bar  (Speech Tools] in my Microsoft Word 2002 and started dictating this Design Idea, the on-screen title displayed "cat" instead of "CAD.   " By using the "Add/Delete Words" feature, I've trained the system to recognize the "CAD" acronym.  This was my first experience with the MOSR  (Microsoft Office Speech Recognition] tool, which is part of the latest Micros __ Circuit Design by Alexander Bell, Infosoft International, Rego Park, NY

Addressable ADC & Controller -  receives serial command then 1) returns adc measurement, and 2) writes output port. Three-byte serial command, three adc inputs, 8 digital outputs, 5-bit address, 9600-baud. (16f873)  __ Designed by Jon Fick

Addressable DALI Dimming Ballast -  A digitally addressable digital dimming ballast has been developed.  It conforms to DALI standard requiring very few parts and operates at very low power.  Applications include building management or studio lighting where it is desired to control single or groups of lamps for conserving energy, performing lamp maintenance or creating prefect light quality.  The design includes the digital dimming ballast, the code of the micro-controller and a platform to control the ballast by PC.   __ Designed by Cecilia Contenti and Tom Ribarich Applications Engineer, International Rectifier, Lighting Group

Adjust negative power supply -  Adjust negative power supply from 7905

Adjustable power supply with LM350 -  1.2 to 20 V, 3A power supply with LM350

Adjustable Strobe Light -  This Adjustable Strobe Light is the bigger brother of the plain old strobe light.  This one uses a much more powerful "horse shoe" Xenon tube which produces more light.  You can also control the flash rate up to about 20Hz.  Do not look directly at the flash tube when this thing is on! __ Designed by Aaron Cake

Adjustable Voltage Motor Controller -  One of the nice things about flying electric is you can test run your motor in the house, workshop, or in the yard and the neighbors won't complain.  The problem is how to control the speed of the motor.  One way is to use the plane, radio, and speed control with the motor in it.  That's no fun! __ Designed by One of the nice things about flying electric is you can test run your motor in the house, workshop, or in the yard and the neighbors won't complain. The problem is how to control the speed of the motor. One way is to use the plane, radio, and speed control with the motor in it. That's no fun! Mount the motor on the bench and just plug the battery into the motor. That's even worse! It's hard on the motor and gearbox.

Advanced TCA Hot Swap Controller Eases Power Distribution -  DN353 Design Notes   __ Linear Technology/Analog Devices

AdvancedTCA Four Fuse Monitoring Application -  The LTC4261 negative voltage Hot Swap controllers allow a board to be safely inserted and removed from a live backplane.  Using an external N-channel pass transistor, the board supply voltage can be ramped at an adjustable rate.  The devices feature independently adjustable inrush current and overcurrent limits to minimize stresses __ Linear Technology/Analog Devices App Note, Mar 26th 2010

AdvancedTCA with High-Side & Low-Side Ideal Diode-OR & Hot Swap Controller with I2C Current & Voltage Monitor -  The LTC4355 is a positive voltage ideal diode-OR controller that drives two external N-channel MOSFETs.  Forming the diode-OR with N-channel MOSFETs instead of Schottky diodes reduces power consumption, heat dissipation and PC board area.  __ Linear Technology/Analog Devices App Note, Mar 26th 2010

Advertising Badge #1 with Flashing LED -  I have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by David Johnson P.E.-March, 2002

Advertising Badge #2 with Flashing LED -  This circuit uses a CD4013 dual D Flip/Flop IC.  A single lithium battery will provide months of continuous LED flashing.  It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by David A. Johnson P.E.-March, 2002

AGC Circuit -  SSB SSB Transceiver-Receiver Section:  The AGC circuit uses a dual op-amp IC.  The first stage amplifies the receive audio   (taken from the hot side of the AF gain control).  The output from this stage is converted to a DC   (ish) signal by a voltage doubling rectifier.  The final stage is a DC amplifier.  A nice feature of the circuit, is that the meter is automatically set at zero, in the absence of any signal.  I used an LF353 dual op-amp.  Most fet input dual op-amps should work in this circuit, or you can use a pair of single op-amps. __ Designed by EI9GQ homebrew radio

AIR-Speed Sensor for Cooling Fan -  Schematic only __ Designed by va3iul

Alarm control keypA - D -  The IC is a quad 2 input "AND" gate, a CMOS 4081.  These gates only produce a HIGH output, when BOTH the inputs are HIGH.  When the key wired to 'E' is pressed, current through R1 and D1 switchs Q5 on.  The relay energises; and Q5 is 'latched on' by R8.  Thus, the Alarm is set by pressing a single key, say one of the two non-numeric symbols __ Designed by Ron J.

Alarm Sounds At Freezing Temperatures -  This electronic hobby circuit below is designed to activate a beeper alarm, whenever the outside air temperature is below 0 degrees C   (32F) .  A 9v battery powers the hobby circuit.  The average 9ua current is so low that the battery should last for many years . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Alarm using Your Own Voice -  This alarm plays your prerecorded voice message.  It is built around the readily available quartz clock.  Take the buzzer out of the quartz clock and connect its positive terminal to pin...__ Electronics Projects for You

All-Digital Fires TRIA - C -  07/21/94 EDN-Design Ideas This digital circuit allows a µP to control ac power precisely without using any digital-to-analog circuitry.    __ Circuit Design by Robert Trescott Jr, GTE ImagiTrek, Carlsbad, CA

Altec 1566A:Vacuum Tube Preamp & Direct Box Project -  There are all sorts of tube circuits, some of which actually deliver The Sound people associate with Vacuum Tubes.    Did you know, for example, that asymmetrical distortion generates even-order harmonics while symmetrical distortion produces odd-order harmonics?  Neither vacuum tubes nor transistors are exclusively responsible for either type of distortion, it’s really about Circuit design

Alternating CW & CCW Motor Driver -  A while back a company needed a motor controller for a custom door latching system.    The system used a small brush motor with a speed reduction gear to both latch and unlatch the door.    When pulsed for about 250ms in the clockwise direction, the motor would unlatch the door. . . Circuit by David Johnson P.E.-September, 2010

Alternating Flasher -  Scroll to find this one.  This circuit uses three easily available 555 timer ICs.  All three work as astable multivibrators.  The first 555 has an on period and off period equal to 1 sec.  This IC controls the on/ off periods of the other 2 555s which are used to flash two bulbs through the relay contacts.  The flashing occurs at a rate of 4 flashes per second

Alternating Flashing Light -  This project is best for mounting on a layout to light a crossing or ring a bell.   __ Designed by ML Rollins

Alternating LED flasher uses minimal parts -  11/20/97 EDN-Design Ideas A pair of alternating flashing LEDs makes an excellent visual alarm, this alternating LED flasher is based on one LED with built-in flashing function and two transistors driving  or normal LED.    __ Circuit Design by Dennis Eichenberg, Parma Heights, OH

Alternating LED blinker uses four parts -  EDN-Design Ideas March 26, 1998    [ NOTE : File has multiple design, scroll for this one.]   The circuit in Figure 1 is an easy-to-make attention-getter and runs for a week or longer on two AA cells. In September, I used this circuit for a school fundraiser, and it helped me generate more than $100. My dad showed me a circuit in EDN that did the same thing, but it uses more parts (see "Alternating LED flasher uses minimal parts," EDN, Nov 20, 1997, pg 104). __ Circuit Design by Andy Meng, Cincinnati, OH

Alternating LEDs Flasher -  Classic astable multivibrator using 2 transistors.  Transistor is not critical.  Try these: 2N4401, 2N2222, NTE123A, NTE123AP, NTE159, TUP/TUN and those in your junk box, you may find that most of them will work.   __ Designed by Tony van Roon  VA3AVR

Amplifier for a Xenon Lamp Flash Detector  -  This circuit has a very low standby current requirement yet has very high sensitivity toward the light flashes from a xenon lamp.  When connected to a flip/flop it can serve as an on on/off Controller. . . Circuit by David A. Johnson P.E.-February, 2002

An 8-Channel PC Relay Board -  Control devices via your PC parallel port with this eight-channel relay board.__ SiliconChip

An Add-On Current Limiter for Your PS - U -  Power Supply Circuits:  This circuit allows you to set a limit on the maximum output current available from your PSU.  It's very useful when you power-up a project for the first timeor carry out a soak-test.  By setting an upper limit on the current available from your PSUyou can protect both your power supplyand any device connected to it.  It offers a simple and cheap alternative to the Current Limiting Power Supply.  __ Designed by Ron J.

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Control Circuits:   #'s - A       B - C       D - G        H - L       M - P        Q - S        T - U        V - Z

 


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