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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.

TV /VCR Remote Range Extender CircuitI often get frustrated by how poor some infrared remotes in many new electronic devices operate.  I used to be able to turn on the TV from 30 feet away.  Now, it seems that I have to get within 15 feet.  To address this issue, I designed the circuit shown below.  The circuit taps into the TV remote’s existing infrared LED and drives 8 more efficient devices.  The result is a communications range some 4 to 5 times longer.. . . Circuit by David A. Johnson P.E.-October, 2005

TV-VCR Light Source 40Khz RepeaterThis circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Two Pushbutton Motor ControllerTwo small pushbutton switches, a few diodes and two relays form a method to control on/off power to a brush motor as well as the motor direction.  The circuit was originally designed for a motorized lifting platform. . . Circuit by David Johnson P.E.-September, 2005


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

TRIAC based lamp dimmer Schematic only, no circuit description __ Contact: IQ Technologies

TRIAC Dimmable 20W Offline LED Driver using the LT3799 -  This circuit shows a complete LED driver solution.  The LT3799 senses the output current from the primary side switch current waveform.  The IC regulates the output current by adjusting the peak switch current and the duty cycle through a novel feedback control.  Unlike other primary side sensing methods that need to know input power and output voltage information, this new scheme provides much better output current regulation since the accuracy is barely affected by transformer winding resistance, switch RDS (ON) , output diode forward voltage drop and LED cable voltage drop__ Linear Technology/Analog Devices App Note, Jul 1, 2011

TRIAC Light Controller -  This project is intended for controlling mains powered disco lighting, although there are many other possible uses for controlling almost any mains appliance.  It will control five seperate channels at up to 3 Amp per channel.  This could be increased by designing another PCB with wider tracks than the PCB included with this design __ Designed by Matthew Hewson

TRIAC Light Dimmer -  This little circuit can be used to dim lights up to about 350 watts.  It uses a simple, standard TRIAC circuit that, in my expirience, generates very little heat.  Please note that this circuit cannot be used with fluorescent lights.   __ Designed by Aaron Cake

TRIAC Light Dimmer -  Schematic only, no circuit description __ Contact: IQ Technologies

TRIAC Light Dimmer -  This little circuit can be used to dim lights up to about350-Watts.  It uses a simple, standard TRIAC circuit that, in my experience, generates very little heat.  Please note that this circuit cannot be used with fluorescent lights __ Contact: IQ Technologies

TRIAC lighting & heating controller uses few parts -  09/02/04  EDN-Design Ideas The TRIAC lighting-control circuit in Figure 1 is small and inexpensive because load and housekeeping power come directly from the line voltage, thereby eliminating bulky, expensive supplies.  The CLZD010 closed-loop controller maint __ Circuit Design by David Caldwell, Flextek Electronics, Carlsbad, CA

TRIAC Switch To Control High-Voltage Devices -  From ages electron-magnetic relays are being used as switches to control high voltage devices.  But, because of their bulky size and noise (both electrical and mechanical) people started using TRIAC with opto-coupler as better alternative.  Above circuit uses TRAIC and Opto-coupler to use small voltage to control high voltage devices.  For example, micro-controller to control 220v bulb or any device which runs on high voltage. __ ` Sigmatone

Tricolor LEDs Create a Flashing Array -  24-Jun-10 EDN-Design Ideas You can build a matrix of RGB(red/green/blue) LEDs using a simple and inexpensive circuit comprising the control logic and driver circuit in Figure 1 and some LEDs(Figure 2).  The center RGB LED is the first to come on, after which each sequential LED in the 8×8-LED matrix follows.  This process gives the appearance that the display is alive and moving outward.  This sequence repeats, producing a rainbow effect of colors __ Circuit Design by Jeff Tregre, www/BuildingUltimateModels/com, Dallas, TX

Triple Stroboscope -  This circuit enables observation of movement between other stroboscopes.  Generation of rectangular signal is based on NE555.  This circuit requires a low power supply that is made from a simple transformer TR1, traditional rectifier bridge and zener diode.  NE555 works in multivibrator mode generating astable pulses of 2Hz to 20Hz.  The frequency is adjusted by potentiometer P1.  The control potentiometer P1 can be placed as far as 30 meters away, for suspension of stroboscope’s work from far away. __ Contact: IQ Technologies

Triple-Mode Tone Generator -  Here is a simple circuit that generates three different tones.  You can use it as a call bell, burglar alarm or any other security alarm.Fig.1 shows the circuit of the...__ Electronics Projects for You

Tube provides linear tuning -  11/05/98 EDN-Design Ideas (File has many circuits, scroll to this one)  Parallel LC circuits that you tune by changing capacitance have a nonlinear frequency-versus-voltage or frequency-versus-shaft-position characteristic.  The frequency of an analog-tuned circuit is proportional to the reciprocal of the square root of the tuning capacitance.  When you tune a bandwidth that is say, 5% or less of the center frequency, the frequency-versus-capacitance __ Circuit Design by Lyle Williams, Electronic Technical Services, New Orleans, LA

Turn on the aquarium lights every day at the same time -  This is a simple one-valve irrigation controller made for our greenhouse.  The code contains a software real-time clock (RTC) and a multiplexed 8-digit LED display and keyboard you can use in other projects.  Turn on the sprinkler or the aquarium lighting for the same period of the day.  You can choose to operate the output by every 2nd, 3rd day only.  There is a manual start/stop button to immediately turn on or off the output, and a disable button to completely turn off automatic operation __ Designed by Peter Jakab

Turn-signal System for Motorcycles -  This circuit is based on the CMOS IC from Motorola, the MC14049UB Hex Inverting Buffer.  Of course, the regular CD4049 can be used and is pin-for-pin compatible.  The 4049 is a 16-pin chip.  Maximum DC supply voltage should not exceed 18V.  The above diagram can replace your existing mechanical clicker.  The prototype worked excellently!__ Tony van Roon  VA3AVR

TV /VCR Remote Range Extender Circuit -  I often get frustrated by how poor some infrared remotes in many new electronic devices operate.  I used to be able to turn on the TV from 30 feet away.  Now, it seems that I have to get within 15 feet.  To address this issue, I designed the circuit shown below.  The circuit taps into the TV remote’s existing infrared LED and drives 8 more efficient devices.  The result is a communications range some 4 to 5 times longer.. . . Circuit by David A. Johnson P.E.-October, 2005

TV Light -  Switch you TV lamp while comfortably seated on you armchair, using your TV's remote control (*).  Of course, you can use the same circuit for a variety of other "comfortable" uses, like controllin a fan or the heating.  Those very versed in electronics DIY could apply it to very unusual devices, like telephones or answering machines.   __ Designed by Projects & Ideas from Nutchip.com

TV Remote Control Jammer -  Scroll to this oneDo you have an incessant channel hopper that is driving you crazy? Or perhaps you simply want to enforce your own selections.  The TV Remote Control Jammer will do the trick.  This circuit is a redo of an older design which is not effective on modern remotes.  Modern remote controls are hard to jam but with a little care this circuit will do the job.  The circuit is just a flasher operating at 40 kHz which is the carrier frequency used by common remote controls.  The strong 40 kHz infrared flashing interferes with the signal from the remote. 
 __ Contact: Charles Wenzel of Wenzel Associates, Inc.

TV-VCR Light Source 40Khz Repeater -  This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Twinkle Twinkle X’mas Star -  Christmas just would not be Christmas if you do not put a flashing star on your Christmas tree.  Here is the circuit of such a flashing star.Fig.1 shows the circuit...__ Electronics Projects for You

Two Basic Motor Speed Controllers -  Here are two simple 12V DC motor speed controllers that can be built for just a few dollars.  They exploit the fact that the rotational speed of a DC motor is directly proportional to the mean value of its supply voltage.  The first circuit shows how variable voltage speed control can be obtained via a

Two Components Drive Stepper Motor -  EDN-Design Ideas 01/19/95    The extremely simple circuit in Fig 1 drives a stepper motor directly from 120V ac, 60 Hz.  Usually you need switched-dc voltages to drive a stepper motor.  But a stepper motor will run off ac lines if you introduce a 90° phase shift between the voltages applied to the motor's two windings. __ Circuit Design by Carl Spearow, Basler Electric,m Highland, IL

Two Light Controlled Relays -  Switching Circuits:  These two circuits use LDRs (Light Dependent Resistors).  Circuit No.1 energizes the relay when the light rises above a preset level. Use it to switch things on at dawn. Circuit No.2 energizes the relay when the light falls below a preset level. Use it to switch things on at dusk.  __ Designed by Ron J.

Two Load-Sharing, Redundant, 48V/10A Power Supplies using an Ideal Diode -  This circuit shows a 48V/10A ideal diode-OR application.  An MBR10100 Schottky diode would dissipate 6W under these operating conditions.  In contrast, the FDB3632 7.5mohm MOSFET dissipates only 0.75W.  The reduced power loss increases efficiency and saves space required for heat sinking.  If the power supply voltages are nearly__ Linear Technology/Analog Devices App Note, Jul 8th 2011

Two Pushbutton Motor Controller -  Two small pushbutton switches, a few diodes and two relays form a method to control on/off power to a brush motor as well as the motor direction.  The circuit was originally designed for a motorized lifting platform. . . Circuit by David Johnson P.E.-September, 2005

Two Signals Easily Control Tricolor LED -  09/14/95 EDN-Design Ideas Tricolor LEDs come in two- and three-pin packages.  Although the three-pin, or common-cathode, package easily lends itself to 2-bit control, wiring three crowded pins can be mechanically difficult.  Also, fewer manufacturers produce the three-pin types.  The two-pin package is easier to connect to a wiring harness and is readily available.  However, this package requires more control overhead, because, to light the LED yellow, the device must continuously alternate between red and green.   __ Circuit Design by Bob Richards, Digital Audio Corp, Raleigh, NC

Two Temperature Controlled Relays -  Switching Circuits:  These two circuits use Thermistors   (Temperature Dependent Resistors).  Circuit No.1 energizes the relay when the temperature rises above a preset level. Use it to switch things on when it gets hot. Circuit No.2 energizes the relay when the temperature falls below a preset level. Use it to switch things on when it gets cold.  __ Designed by Ron J.

Two Tone Generator -  This two-tone generator includes 3 ICs NE555 Astable Multivibrators.  You can vary the duration of each tone by changing the 10k resistor or 100MF capacitor at IC1 or changing resistors and capacitors at IC1/2 for higher or lower tone.   __ Designed by Andrew R. Morris

Two tone mixer IIP3 Notes -  As a measuring experimenter with a homebrew POV, I like to add new test equipment and procedures to my lab each year.  With digitally processed spectrum analyzers getting more able and relatively cheaper over time, I think a spectrum analyzer (with a built in tracking generator) might prove one of the best toys to consider buying.  As ever, a homebrew SA remains a valid option for more advanced builders. __ Contact: Vasily Ivanenko

Two Transistor Flasher -  The basic two-transistor flasher shown below has found its way into dozens of applications due to its simplicity and versatility.  Applications have included such diverse circuits as a micropower low battery indicator, a lightning detector, a off-line.   __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Two Transistor FM Transmitters -  While there are a plethora of similar 2-transistor schematics available, this one is above average.  A major improvement overlittle 1-transistor circuit that we've discussed previously, this transmitter consist of two stages.  first transistor is used to amplify audio, 

Two Transistor LED Flasher -  This circuit will flash a bright red LED as an attention getting device or fake care alarm. __ Designed by Bill Bowden

Two Transistor LED Flasher -  This is a classic 2 transistor astable multivibrator.  Many other NPN small signal or switching transistors can be used, including 2N4401, PN2222 or 2N2222 using the circuit on the left.  The circuit can also be inverted using PNP transistors such as 2N3906, 2N4403, PN2907, or 2N2907 as shown to the right __ Designed by Bill's Electronics Reference Library

Two Transistor LED Flasher 1 -  Circuit Only __ Designed by Tony van Roon  VA3AVR

Two Transistor LED Flasher 2 -  This circuit will flash a super-bright LED (5000+ mcd).  Good for fake car alarm or other attention getting device.  Component values are not critical, try anything else first from your junkbox.  Obviously, the 470 ohm resistor (R3) determines the LED's brightness and limits the current flow to about 20mA.390 ohm can also be used as a save value.  If you decide to go with a green or yellow led, which draw more current, you may want to replace the 470 ohm with an appropriate value.  Flash rate is determined by R2 and C1 __ Designed by Tony van Roon  VA3AVR

Two transistor lights LEDs -  04/09/09  EDN-Design Ideas A previous Design Ideasdescribes a circuit that uses an astable multivibrator to drive an LED   (Reference 1].  The circuit in Figure 1 uses a simpler alternative approach.  The circuit uses a 2N3904 NPN transistor and a 2N3906 PNP trans __ Circuit Design by Barry A Tigner, Michigan State University, East Lansing, MI

Two Watt Amplifier -  A 2 Watt audio amplifier made from discrete components.  This was one of the earliest circuits that I ever designed and built, in Spring 1982.  At that time I had only an analogue meter and a calculator to work with.  Although not perfect, this amplifier does have a wide frequency response, low harmonic distortion about 3%,  __ Designed by Andy Collison

Two Watt Amplifier -  An audio amplifier made from discrete components with 2 Watts audio power into an 8 ohm load.  Carlos has used this amplifier on his AM radio for many years.   __ Designed by Carlos Feldman

Two Wire Stepper Motor Positioner -  A simple and inexpensive way to remotely rotate a display or object is with a positioner that uses a stepper motor to rotate it.  The motor is driven by a circuit mounted near the motor and by a control circuit at a remote location.  __ Golab.com

Two-button control for dangerous machines -  Two button control systems are used on dangerous industrial machines in order to protect the operator’s hands.  Just for hobby I made a circuit that turns on a relay by pressing two buttons simultaneously.   __ Designed by Andrea-Central Italy

Two-Chips Simplify Layout for High-End Embedded Control -  04/01/99 EDN-Design Ideas NOTE :  File contains many designs.   Scroll to this one.   If you are considering using one of the 32- or 64-bit RISC µPs from Integrated Device Technology  (IDT], the company’s new RC32134 and RC64145 system-controller ICs (Picture] can make your job easier.  The chips provide synchronous-DRAM, memory, and I/O control; a PCI interface; and peripherals, including UARTs, timers, and interrupt controllers.  The 32134 for the RC32364 µP provIdeas a glueless interface to DRAM Page includes several designs.   __ Circuit Design by Graham Prophet

Two-wire DC Lamp Dimmer replaces Rheostats -  10/23/97 EDN-Design Ideas Originally for use in commercial trucks, a low-cost dc lamp dimmer   (Figure 1) can control more than 100W of incandescent panel lighting and replaces a high-power rheostat, whose heating darkensinstrument panel.   __ Circuit Design by Kevan O'Meara, KO Systems, Chatsworth, CA

Two-wire Lamp Flasher -  This circuit was designed to provide that continuous light lamps already wired into a circuit, become flashing. Simply insert the circuit between existing lamp and negative supply. __ Contact: Flavio Dellepiane, fladello @ tin.it

Two-wire remote sensor preamp -  01/13/14  EDN-Design Ideas Locally condition and amplify a distant sensor using only a two-wire connection for both power and signalThis Design Idea implements a remote sensor preamp   (e.g., for a piezoelectric transducer) which transfers both signal and power over a single wire pair or coax __ Circuit Design by Vladimir Rentyuk

Type 1 Solar Engine-voltage controlled trigger -  Voltage controlled triggerThis is by far the predominant form of solar engine, since they are "efficient enough" for most uses, and pretty simple to build.   __ Contact: Eric Seale

Type 2-Solar Engine-time controlled trigger -  Time controlled triggerThese aren't terribly efficient, but are handy for 'bots that need activity at specific times.   __ Contact: Eric Seale

Type 3-Solar Engine-charge curve differentiated -  Charge curve differentiated (i.  e.  , it triggers when the charge rate of the capacitors slow down) -- These are theoretically the most efficient, though type 3 designs are still in their infancy.   __ Contact: Eric Seale

Typical Strobe Light Trigger -  555 based Timing circuit which triggers a SCR which controls the trigger transformer __ Designed by Don Klipstein

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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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