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Control Circuits

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Last Updated: October 18, 2017 05:04 AM

Circuits Designed by Dave Johnson, P.E.

Ten-LED Sequential Flasher using Low PowrA while back I posted a flasher circuit which flashed 10 LEDs sequentially.  That circuit was powered by four AA alkaline cells.  The circuit below operates much the same way but has been modified to run from a single 3v CR2032 lithium coin cell. . . Circuit by David Johnson P.E.-April, 2011

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

T V Remote Control Blocker -  Don't like your little brother's TV channel selection? Hate the volume your wife sets the stereo at? Want to just annoy someone?This circuit does all that and more by jamming most IR remote signals.  The circuit releases a flood of pulsing IR light that confuses the reciever by corrupting the data stream __ Designed by Aaron Cake

Tacho generator rectifier -  This page is a bit different from most in that it covers the use of tacho generators as feedback elements in motor control systems.  It also covers a 'Tacho Feedback Board' extra for our Pro-120 and other controllers.  It also includes the circuit diagram.  It thus should be of interest not only to potential customers but also to electronic engineers.   __ Designed by Richard Torrens

Tail/Brake Light Signal Cluster -  Designed at the request of several correspondents, the circuit is the merger of two existing designs already available on this site, namely: LED driven tail/brake Light Cluster and Brake Light Signal Module. __ Contact: Flavio Dellepiane, fladello @ tin.it

Tank Heater -  a PWM power controller used to control the temperature in a tank for a tarantula __ Contact: P. Townshend EduTek Ltd

Telephone Operated Remote Control using PIC16F84a MicroController -  This design controls up to 8 devices using a PIC microcontroller (PIC16F84A) connected to the phone line.  The unique feature here is that unlike other telephone line based remote control, this device does not need the call to be answered at the remote end so the call will not be charged.  This device depends on number of rings given on the telephone line  __

Teleremote Control -  Here is a teleremote circuit which enables switching ‘on’ and ‘off’ of appliances through telephone lines.  It can be used to switch appliances from any distance, overcoming the limited range of...__ Electronics Projects for You

Temperature Alarm -  A simple op-amp circuit that will trigger a relay when a preset temperature is reached.  Please note that there is no hysteresis in this circuit, so that if the temperature changes rapidly, then the relay may switch rapidly.   __ Designed by Andy Collison

Temperature Based Fan Speed Control & Monitoring using Arduino -  This project is a standalone automatic fan speed controller that controls the speed of an electric fan according to the requirement.  Use of embedded technology makes this closed-loop feedback-control system efficient...__ Electronics Projects for You

Temperature Controled Fan -  This circuit controls very accurately a fan of any size.    Just adjust the associated resistors for a different type and you're all set.    The above circuit diagram is for a small cpu-fan, rated 12V at 12mA current.   __ Designed by Tony van Roon  VA3AVR

Temperature Controlled NiCad Charger -  This circuit is for a temperature controlled constant current battery charger.  It works with NICD, NIMH, and other rechargeable cells.  The circuit works on the principle that most rechargeable batteries show an increase in temperature when the cells becomes fully charged.  Overcharging is one of the main causes of short cell life, hot cells pop their internal seals and vent out electrolyte.  As cells dry out, they lose capacity.  This circuit can quickly charge a rechargeable battery pack without any negative effects.  This circuit uses a 22VDC power supply, my version 2 circuit will run from a 12VDC supply such as a solar-powered or automobile power system. __ Designed by G. Forrest Cook

Temperature Controlled Ovens -  Here is a simple temperature controller suitable for a variety of purposes; it was designed to heat the copper float out of a toilet for a barometer! __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Temperature controlled TRIAC for a fan -  Schematic only __ Designed by G.L. Chemelec

Temperature Controller -  The LM3911 requires only a few resistors and capacitors to turn it into a full-function temperature controller.    The schematic diagram illustrates the simplicity of the overal circuit.    The resistor network consisting of R1, R2, and R3 are used to provide the set point voltage for the feedback input of the LM3911 __ Designed by Tony van Roon  VA3AVR

Temperature Controller Drives Peltier Cooler -  06/08/95 EDN-Design Ideas The circuit in "Peltier element controls itself," by Dmitrii Loukianov (EDN, October 27, 1994, pg 86) is elegant, but it suffers from two potential problems that could arise in some applications.  The first is possible switching-noise injection from capacitive and inductive coupling at the front end of a sensitive analog-signal-conditioning chain (for example, in a CCD-cooling application).  The second potential problem is Peltier-stack performance degradation from intermittent, fast-switching drive current.  At least one UK-based Peltier-cooler manufacturer recommends uninterrupted dc drive.    __ Circuit Design by Dr Trevor Preston, Cambridge, UK

Temperature controller has "take-back-half" convergence algorithm -  09/15/05 EDN-Design Ideas Enhanced closed-loop control balances stability, responsiveness __ Circuit Design by W Stephen Woodward, University of North Carolina, Chapel Hill, NC

Temperature controller keeps IR Detector at 8ºK -  01/07/99 EDN-Design Ideas Sensitive infrared array detectors must operate at a low temperature to avoid thermally generated dark current throughout the photoconductive elements.  This requirement is particularly true for SiAs array detectors, which Page includes several designs.  Scroll to find this one __ Circuit Design by Jerry Penegor, Space Sciences Laboratory, University of California—Berkeley

Temperature controller saves energy -  3-Feb-05 EDN-Design Ideas Given the high cost of electrical power, replacing a conventional on/off temperature control with a proportional controller can often save energy and money.  Figure 1 shows a low-cost, high-efficiency, time-proportional temperature controller for a residential water heater.  An Analog Devices ADT14, IC1, serves multiple functions as a temperature sensor, quad-setpoint, programmable analog tempe __ Circuit Design by Tito Smailagich, ENIC, Belgrade, Yugoslavia

Temperature Data Logger -  This project will show you how to build Temperature Logger using a Stamp II connected to a PC serial port.  I was planing on using the DS1620, but used a LM335 temperature sensor because it only needs a two wire interface and it is easy to waterproof.  All i did to waterproof it was to put some heat srink tubing around the 3 wires then around the hole sensor __ Designed by shaunwilson19 @ yahoo.com

Temperature Logger for the Fridge -  NOTE : Must register on this site __ Designed by Published in Elecktor July/Aug, 2010

Temperature Monitor & fan controller reduce fan noise -  01-May-01 EDN-Design Ideas The scheme in Figure 1 reduces system acoustic noise by running system fans at their optimum speeds for a given temperature.  IC1  combines ±1°C-accurate temperature measurement of three temperatures with automatic fan-speed control of two channels.  A two-wire serial interface allows you to oversee critical temperature and fan-speed data __ Circuit Design by David Hanrahan, Analog Devices Inc, Limerick, Ireland

Temperature Monitor measures three thermal zones -  12/11/03 EDN-Design Ideas You can use an ADT7461 single-channel temperature monitor; an ADG708 low-voltage, low-leakage CMOS 8-to-1 multiplexer; and three standard 2N3906 pnp transistors to measure the temperature of three separate remote thermal zones (Figure 1).  Multiplexers have resistance, RON, associated with them; the channel matching and flatness of this resistance normally result in a varying temperature offset.  This system uses the ADT7461 temperature monitor, which can automatically cancel resistances in series with the external temperature sensors, allowing its use as a multichannel temperature monitor.   __ Circuit Design by Susan Pratt, Analog Devices, Limerick, Ireland

Temperature Monitor using 741 opamp -  A simple op-amp circuit that will trigger a relay when a preset temperature is reached.  Please note that there is no hysteresis in this circuit, so that if the temperature changes rapidly, then the relay may switch rapidly.   __ Designed by Andy Collison

Temperature Monitor with Alarm -  This temperature monitor alarm circuit continuosly monitors the room temperature and beeps when the temperature drops below 20 degrees centigrade.  This capability to constantly monitor the room temperature can help lower your air-conditioning costs by reminding you to turn off your airconditioner.  An optical display like a __ Designed by Popescu Marian

Temperature Programmer Uses Digital Control -  07/18/96 EDN-Design Ideas The circuit in Fig.1 is useful for precise, repetitive temperature control of small-volume objects.  It offers high resolution and effective isolation between the control lines and the power mains.  It generates no RFI, has adequate speed, and provIdeas a linear relationship between the digital-input code and the average thermal power supplied by the heater.  The circuit works by generating a programmable number of triggering pulses to a TRIAC connected in series with the heater __ Circuit Design by Jordan Dimitrov, N Poushkarov Institute of Soil Science and Agroecology, Sofia, Bulgaria

Temperature Recorder. Part 1 -  This project uses a Microchip PIC microcontroller, a serial EEPROM and a thermistor to create a temperature recorder.  Performance The temperature is measured and stored at user programmable intervals; this can be from 1 __ Designed by Andrew M. Bishop

Temperature Recorder. Part 2 -  Software PIC Software The PIC software is written in assembler and based on earlier projects using I 2 C interfaces.  The EEPROM, PIC and external connector all share the same I 2 C bus and the PIC will not use it unless the thermistor is fitted.  

Temperature Sensor Control -  A basic circuit using Diodes to detect temperature differences __ Designed by G.L. Chemelec

Temperature-controlled 12V DC Fan -  Suitable for computer cooling fans.  LED motor speed indicator.   __ Contact: Flavio Dellepiane, fladello @ tin.it

Temperature-Measurement Scheme Uses IR Sensor & Sigma-Delta ADC -  3-Apr-03 EDN-Design Ideas Many noncontact temperature-measurement systems use infrared sensors, such as thermopiles, which can detect small amounts of heat radiation.  Biomedical thermometers that measure the temperature of an ear or a temple use noncontact temperature measurement, as do automotive-HVAC systems that adjust temperature zones based on the body temperature of passengers __ Circuit Design by Albert O'Grady and Mary McCarthy, Analog Devices, Limerick, Ireland

Ten-Channel LED Sequencer -  The 4017 is a CMOS decade counter with 10 decoded outputs.  Inputs include a clock   (pin 14) , a reset   (pin 15) , and a clock inhibit   (pin 13) __ Designed by Bill Bowden

Ten-Channel Light Controller -  A 10 channel light controller using PWM/ up to 1a per channel at 12v __ Contact: P. Townshend EduTek Ltd

Ten-LED Chaser -  I don't know why, but people like blinking lights.  You see LED chasers everywhere, in TV shows   (Knight Rider) , movies, and store windows.  This schematic is my version of a simple 10 LED chaser.  There is no 555 timer used because __ Designed by Aaron Cake

Ten-LED Sequencer -  Schematic only, text in Finnish

Ten-LED Sequential Flasher using Low Powr -  A while back I posted a flasher circuit which flashed 10 LEDs sequentially.  That circuit was powered by four AA alkaline cells.  The circuit below operates much the same way but has been modified to run from a single 3v CR2032 lithium coin cell. . . Circuit by David Johnson P.E.-April, 2011

Test Continuity -  This is another invaluable piece of test equipment for digital work.  It has been designed by us to cater for a particular application servicing digital projects sent in for repair.   __ Designed by Collin Mitchell

Test Continuity -  Several simple circuits were tried -a lamp, battery and probes still demanded the attention of the eyes; replacing the lamp with a buzzer was more successful but needed some three to four volts and gave no indication of a series semiconductor.   __ Designed by Tony van Roon  VA3AVR

Tester Checks Christmas-Tree Lights -  12/23/99 EDN-Design Ideas Why is it that you always test 48 bulbs before you find the bad one in a 50-light string? This simple circuit allows you to divide and conquer, greatly reducing the time it takes to find the bad bulb. __ Circuit Design by William Dias, Brown & Sharpe, North Kingstown, RI

Tester for Remote Control -  Here is a simple tester for checking the basic operations of an infrared remote control unit.  It is low-cost and easy to construct.  The tester is built around infrared receiver module TSOP1738....__ Electronics Projects for You

The "Miller engine"Type 1 (Voltage Controlled) Solar Engine -  This is a slightly more-sophisticated design based on a 1381* voltage discriminator. __ Designed by Wilf Rigter

The Battery Eliminator -  The Battery Eliminator Circuit, or BEC, is one of the tools at our disposal to reduce weight in our electric models.  A typical four-cell 600mAh nickel cadmium (NiCd) battery supplied.   __ Designed by Stefan Vorketter

The BEAM Stepper drive -  The 74AC240 stepper driver works by alternately enabling each half of the buffer.  Only one half can be enabled at a time.  Let's assume that the top half of the driver is enabled.  U1A & U1B along with R8, C1, and the input protection resistor R7 form a square wave oscillator.  The outputs of U1A & U1B directly drive one coil of a bipolar stepper motor.   __ Designed by Duane Johnson and Wilf Rigter

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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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