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Control Circuits

 
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Last Updated: October 13, 2017 03:04 AM

Circuits Designed by Dave Johnson, P.E.

Dark Activated 12v Power Supply SwitchUsing an inexpensive phototransistor, this circuit switches 12v to 24v power to a load, whenever the sun goes down . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Detect Short Xenon Lamp FlashesThis circuit uses a small 2.5mm square photo diode in conjunction with a 100mH coil to detect the short light flashes from a xenon lamp.  The coil makes the circuit immune to normal room lights.  Its 10mv sensitivity can detect light flashes from a range of over 100 feet. . . . Hobby Circuit designed by David Johnson P.E.-February, 2002

Detector/Switch for Audio SignalFor some audio systems it is desirable to have an automatic switch circuit turn on other devices, such as an amplifier, if an audio signal is detected on one line.  The hobby circuit below will activate a transistor switch when it detects at least 50mv peak to peak of an audio signal.  The switch could be used to turn on a relay, routing the signal to where it is needed.  A single 3v lithium cell will power the electronic circuit for about 5 years . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Detects Low Voltage 120VAC Power Line  - This hobby circuit will turn on a beeper when the line voltage drops below 100 volt AC . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Detects Xenon Lamp FlashThis 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 . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2004


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

DAC Controlled 100mA Current Source -  The LT3092 easily interfaces with an external DAC to allow digital current control.  __ Linear Technology/Analog Devices App Note, Mar 24th 2010

Dancing LEDs -  LED sequencer: follows the rhythm of music or speech; 9V Battery-operated portable unit __ Contact: Flavio Dellepiane, fladello @ tin.it

Dark Activated 12v Power Supply Switch -  Using an inexpensive phototransistor, this circuit switches 12v to 24v power to a load, whenever the sun goes down . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Dark Activated Switch -  This circuit will activate a relay when light falls to a preset level.  Light level can be adjusted with VR1 and the relay contacts may be used to operate an external light or buzzer.   __ Designed by Andy Collison

Dark Activated Switch-DAS1 10A/12V -  The DAS1 is a combination manual switch and automatic dark-activated switch.  It is designed to control up to 10 amps of 12V lights.  A pair of high-intensity white LEDs are included in the circuit for built-in lighting.  The circuit includes a low voltage disconnect circuit that prevents excessive battery discharge on battery operated systems.  The DAS1 is ideal for solar powered lighting systems, it can also be used for line powered and automotive/marine applications.  External 12V lights consisting of white LEDs, incandescent lamps and/or fluorescent lamps can be driven by the DAS1. __ Designed by G. Forrest Cook

Dark Sensitive Switch -  Dark Sensitive Switch is a simple project which operates a relay when the light falling on the LDR goes below a set point __ Designed by Rajkumar Sharma

Dark/Light Activated Relay -  The potmeter adjust the trigger 'on' level.  The diode in the diagram shows to be 1N914.  This is ok if you have a light-duty relay, also the 1N914 is a signal diode so actually does not qualify.  Use a 1N4001 (Tony van Roon's or better) instead.  A couple of substitutes for the 2N2222 transistor are: NTE123A, ECG123A, PN100, etc __ Designed by Tony van Roon  VA3AVR

Dark-Activated 230V Lamp -  Compact circuitry using small-size parts only; Can be wired in parallel to existing switches __ Contact: Flavio Dellepiane, fladello @ tin.it

Dark-activated LED or Lamp Flasher -  This circuit adopts the rather unusual Bowes/White emitter coupled multivibrator circuit.  The oscillation frequency is about 1Hz and is set by C1 value.   __ Contact: Flavio Dellepiane, fladello @ tin.it

DAS1 10A/12V Dark Activated Switch -  The DAS1 is a combination manual switch and automatic dark-activated switch.  It is designed to control up to 10 amps of 12V lights.  A pair of high-intensity white LEDs are included in the circuit for built-in lighting.  The circuit includes a low voltage disconnect circuit that prevents excessive battery discharge on battery operated systems.  The DAS1 is ideal for solar powered lighting systems, it can also be used for line powered and automotive/marine applications.  External 12V lights consisting of white LEDs, incandescent lamps and/or fluorescent lamps can be driven by the DAS1. __ Designed by G. Forrest Cook

Daytime Running Lights Controller -  Auto makers have been gradually switching to light emitting diode (LED) lighting for automotive headlamps because of its features such as high efficiency and long service life.  In addition, from a...__ Electronics Projects for You

DC Motor Control -  This circuit uses solid state switching (transistors) to control direction of a DC motor.  You have precise control of the movement of the motor, and an indication of direction provided by LED's.   __ Designed by Andy Collison

DC Motor Control using a Single Switch This simple circuit lets you run a DC motor in clockwise or anti-clockwise direction and stop it using a single switch.  It provides a constant voltage for proper operation of the...__ Electronics Projects for You

DC Motor Control using PWM -  Small DC motors are efficiently controlled using pulse-width modulation (PWM) method.  The circuit described here is built around an LM324 low-power quad-operational amplifier.  Of the four op-amps (operational amplifiers) available in this IC, two are used for triangular wave generator and one for comparator. STUTEE SAXENA

DC Motor Driver with L6203 -  The L6203 is a DMOS full bridge driver, which can handle the high peak current up to 5A and supply voltage up to 48V with RDS (ON) of just 0.3 ohm.  The chip can run the DC motor at 4A continuous with proper heat sinking.  The above DC motor driver circuit is implemented with L6203 chip accompanied by a L6205 current controller.  The current controller is used in this circuit as a pair of latching comparators.  When the current through the motor reaches __ Designed by www.wzmicro.com

DC Motor Model -  Although SPICE does not provide explicit models for electro-mechanical devices, like a DC motor, creating one is fairly straightforward.  You just need to remember that most physical behaviors, whether mechanical or electrical, can be described by a set of equations.  So for a desired (spice design) 

DC Motor Pulse Width Modulation Speed Control -  This is a circuit for controlling the speed of small DC motors, it works nicely as a speed controller for an HO or N gauge model railroad.   __ Designed by G. Forrest Cook

DC Motor Reversing -  A DC motor reversing circuit using non latching push button switches.  Relays control forward, stop and reverse action, and the motor cannot be switched from forward to reverse unless the stop switch is pressed first __ Designed by Andy Collison

DC Motor-Driver H-Bridgedb -  Physical motion of some form helps differentiate at from a computer.  It would be nice if a motor could be attached directly to a chip that controlled the movement.  But, most chips can't pass

DC Push Button Motor Control -  This circuit uses solid state switching (transistors) to control direction of a DC motor.  You have precise control of the movement of the motor, and an indication of direction provided by LED's.   __ Designed by Andy Collison

DC Relay Switch for High-Current Loads -  Want to switch power to a high-current load using a circuit capable of supplying just a few milliamps? No problembuild and use the SILICON CHIP DC Relay Switch.__ SiliconChip

DC servo Motor driver -  site is currently under construction __ Contact: IQ Technologies

DC Servomotor Controller -  An experiment on the DC servomotor control system.  It is controlled with only an AVR.    __ Designed by The Electronic Lives Manufacturing-presented Chan

DC/DC Controller Generates Negative Supply -  06/08/95 EDN-Design Ideas A Switch mode Power Supply controller plus a diode capacitor network generate the modest negative Supply Current needed for OpAmps or for LCD Bias, without inductors.    __ Circuit Design by Michael Keagy, Maxim Integrated Products, Sunnyvale, CA

DC/DC converter operates from phone line -  01/15/98 EDN-Design Ideas DC/DC converters for use inside the telephone handset require operation from the high-source-impedance phone line.  Additionally, the CCITT specifications call for maximum on-hook power consumption of 25 mA.  The DC/DC converter in Figure 1 is 70%-efficient at an input power of 25 mA, providing 5V at 3.4 mA.  Controlled, low-peak switch __ Circuit Design by Gary Shockey, Linear Technology Corp, Milpitas, CA

DC-motor switch with brake -  10-Jan-02 EDN-Design Ideas Controlling a small dc motor without speed control sounds like a trivial task; a switch or a relay should suffice.  However, several problems accompany this approach.  For one, the switch, because of the inductive load and the low starting resistance of the motor, tends to wear out prematurely(with all the related sparks and EMI problems] __ Circuit Design by JB Guiot, DCS AG, Allschwil, Switzerland

Debugging an MCU-based CCD camera Controller -  Application Note__ Aligent

Decorative light Controller -  Dimmer control is often used to change the brightness of the light with AC.  Bidirectional thyristor (TRIAC) is used for controlling current.  The circuit which controls a thyristor using a variable resister and a capacitor is common.  The circuit introduced on this page is a circuit which controls a thyristor by software of PIC.  It is also possible to make control the electric bulb on a Christmas tree bright gradually and dark gradually.  Blink control of various patterns can be performed.   __ Designed by Seiichi Inoue

Deer Repellent -  Here is a simple sensor which can detect the seismic vibrations caused by a person or large animal walking nearby.  A representative application for the sensor is a deer repellent for the vegetable garden __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Delay Unit for Surround Sound -  The Mitsubishi M65830 Delay IC has been discontinued (for reasons beyond my comprehension) , and so far a suitable replacement device has not been found.  This means (of course) that you will be unable to build this delay circuit.  I have left the project in place as reference, and the overall connection schematic is still valid if (when?) a replacement for the M65830 is located.  The project will be updated at that time.  In the meantime, just ignore the delay circuit __ Designed by Rod Elliott  ESP

Delayed Audible Alarm -  In this circuit, three multivibrator-type oscillators and a ripple counter are configured to produce an interesting, alarming sound, using two inexpensive integrated circuits plus a few other components.  Operation is as follows:U1A and U1B and their associated components are configured as multivibrators, each of a selected audio frequency __ Designed by Arthur Harrison

Delayed Power using an SCR -  This circuit Creates a Tiny Power Delay to a Circuit.  Read Why I designed it.   __ Designed by G.L. Chemelec

Delayed Start for Appliances -  Your washing machine lacks this useful feature? This special timer will power it only when you want to.  Say goodbay to creasy clothes because of the time spent waiting in the machine.  And if your problem is limited overall electric power, you can set up the washing machine and the dishwater at the same time, having them working at different hours __ Designed by Projects & Ideas from Nutchip.com

Deliver Dimming Control for White-LED Driver -  10/28/04  EDN-Design Ideas The demand for power in color cell-phone handsets is constantly increasing.  New applications steadily emerge, making it imperative to reduce power consumption in the design.  Examination of usage data shows thatthan 50% of the power __ Circuit Design by Wallace Ly, National Semiconductor, Santa Clara, CA

Descrete Multistage Light Sequencer -  The drawing below illustrates a multistage light sequencer using descrete parts and no integrated circuits.  The idea is not new and I hear a similar circuit was developed about 40 years ago using germanium transistors.  The idea is to connect the lights so that as one turns off it causes the next to turn on, and so forth.  This is accomplished with a large capacitor between each stage that charges when a stage turns off and supplies base current to the next transistor, thus turning it on.  Any  __ Designed by Bill Bowden

Design Notes 503: Dual DC/DC Controller for DDR Power with Differential VDDQ Sensing & ±50mA VTT Reference -  11/01/13  EDN-Design Notes   Solid-state circuit breaker for microcontrollers.  The LTC3876 is a complete DDR power solution, compatible with DDR1, DDR2, DDR3, and DDR4 lower voltage standards.  The IC includes VDDQ and VTT DC/ DC controllers and a precision linear VTT reference.  A differential output sense amplifier and precision internal reference combine to offer an accurate VDDQ supply.  The VTT controller tracks the precision VTTR linear reference with less than 20mV total error.  The precision VTTR reference maintains 1.2% regulation accuracy, tracking one-half VDDQ over temperature for a ±50mA reference load.   __ Circuit Design by Ding Li

Design Notes 504: 42V 2.5A Synchronous Step-Down Regulator with 2.5μA Quiescent Current -  11/26/13  EDN-Design Notes   Measure inductance & capacitance over a wide range.  The LT8610 and LT8611 are 42V, 2.5A synchronous step-down regulators that meet the stringent high input voltage and low output voltage requirements of automotive, industrial, and communications applications.  To minimize external components and solution size, the top and bottom power switches are integrated in a synchronous regulator topology, including internal compensation.  The regulator consumes only 2.5μA quiescent current from the input source even while regulating the output.   __ Circuit Design by Hua  Walker Bai

Design Notes: Dual controller provides 2μs step response & 92% efficiency for 1.5V rails -  12/29/13  EDN-Design Notes   Use a heated diode as a flow sensor.   The LTC3838 is a dual output, dual phase buck controller that employs a controlled constant on-time, valley current mode architecture to provide fast load step response, high switching frequency, and low duty cycle capability.  The switching frequency range is 200kHz to 2MHz—its phase-locked loop keeps the frequency constant during steady-state operation and can be synchronized to an external clock.  The LTC3838 accepts a wide input range, 4.5V to 38V, and can produce 0.6V to 5.5V outputs. __ Circuit Design by Linear Technology Design Note 505

Detect Short Xenon Lamp Flashes -  This circuit uses a small 2.5mm square photo diode in conjunction with a 100mH coil to detect the short light flashes from a xenon lamp.  The coil makes the circuit immune to normal room lights.  Its 10mv sensitivity can detect light flashes from a range of over 100 feet. . . . Hobby Circuit designed by David Johnson P.E.-February, 2002

Detector/Switch for Audio Signal -  For some audio systems it is desirable to have an automatic switch circuit turn on other devices, such as an amplifier, if an audio signal is detected on one line.  The hobby circuit below will activate a transistor switch when it detects at least 50mv peak to peak of an audio signal.  The switch could be used to turn on a relay, routing the signal to where it is needed.  A single 3v lithium cell will power the electronic circuit for about 5 years . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Detects Low Voltage 120VAC Power Line  -  This hobby circuit will turn on a beeper when the line voltage drops below 100 volt AC . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

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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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