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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.

Night Light from White LEDAs many of you know, I have a pet peeve with poorly made LED night lights.  Often, the light from the LED quickly fades, so within months, the light is useless.  I have posted several versions of modified night lights using higher quality components. . . Circuit by David Johnson P.E.-November, 2008

One-Watt White LED Night LightAs many of you know, I have a pet peeve with poorly made LED night lights.  Often, the light from the LED quickly fades, so within months, the light is useless.  I have posted several versions of modified night lights using higher quality components.  This circuit is yet another version, which produces much more light than those other designs. . . . Hobby Circuit designed by David A. Johnson P.E.-November, 2008

Optical Filter using Color Film NegativeThis isnt an electronic circuit but the file shows the curve for an optical filter made from exposed color film.  The material blocks most visible light but is very transparent to 880nM infrared light.  Kodak 100ASA is exposed to "cool white" fluorescent light for about 5 seconds . . . Hobby Circuit designed by David A. Johnson P.E.-January, 1998

Over-Temperature Micro-Power AlarmThe circuit is powered for years by a single 3 volt lithium battery.  It sounds an alarm when the temperature exceeds a certain point.  With some minor changes the circuit could also be configured for an under temperature (freeze) alarm.  The circuit uses a . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000


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

NE555 Pulse Width Modulator -  This circuit is capable of regulating 12V motors and DC light bulbs.  No coolrib required for Q1 or D3 if the current does not exceed 2A.  If it does, a sufficient coolrib for both the Schottky Diode (D3) and MOSFET Q1 is required __ Designed by Tony van Roon  VA3AVR

Neon Desklamp -  This circuit will power a 6 inch 4 Watt fluorescent tube off a 12 volt supply, consuming 300 mA.  It may also be powered by a suitably rated universal AC/DC adapter.  Advantages of the design are: good light, low power consumption, and readily available stock parts.   __ Designed by Rev. Thomas Scarborough

Neon Tube Modulator for Cars -  Simple circuit connects to the sub-woofer output and modulates a neon light to the beat of the bass__ SiliconChip

NESblinky-Nintendo Controller Bike Flasher -  I saw the "Light Up Your Ride" contest, and I pondered about what could be re-purposed to increase the visibility of my bike, all while hopefully blinding a motorist or two into a fit of retro rage.  I happened upon an old broken Nintendo controller, which made me think of all the superfluous NES controller mods I had seen before.  This sparked a  __ Designed by Randy Linscott

Night Alert -  Idea of this circuit came to me a midnight when my pet dog started barking continuously on sensing a moving shadow, perhaps that of an intruder.  Dogs have a night adaptation capability to maximise the sensitivity of vision in low light.  They are well adapted to see moving objects rather than stationary ones in darkness.    This circuit turns a lamp on for a short duration when the dog barks, giving an impression that the occupants have been alerted.__ Electronics Projects for You

Night Light from White LED -  As many of you know, I have a pet peeve with poorly made LED night lights.  Often, the light from the LED quickly fades, so within months, the light is useless.  I have posted several versions of modified night lights using higher quality components. . . Circuit by David Johnson P.E.-November, 2008

Night-Light Uses a Photoresistor to Detect Dusk -  12/15/11Design Ideas: You can adjust this battery-powered circuit for different levels. __ Circuit Design by Chau Tran, Analog Devices, Malden, MA

No Hassel 3rd Brake Light -  This circuit is NOT a pulser or flasher! What's so special about this circuit? Well, the first third-brake light I installed I had to pull a wire from the Third Brake Light all the way underneath the carpet to the brake-pedal-switch and I thought it would be easier to pluck the signal of both brakelights via the trunk.  Bench-test your circuit first and apply power to the circuit,  __ Designed by Tony van Roon  VA3AVR

Nocturnal Animals Whisker -  A low-rate flashing lamp drives away undesired visitors; Automatic on-off operation __ Contact: Flavio Dellepiane, fladello @ tin.it

Nocturnal--solar engine -  Nocturnal -- These solar engines charge up when it's light, and discharge (i.  e.  , power a load) when it's dark.  Nocturnal solar engine designs are built for just one thing -- to provide power to a nighttime load.  This means that unlike other SE designs, they charge continuously when there's light, then only release their power when it's dark -- essential behavior for BEAMbots that you only want to be active at night -- "crickets", night-lights, "pummers", and other such ornaments.   __ Contact: Eric Seale

No-Hum Fan Controller -  Control is derived from the output of regular wall switch.  The signal is filtered to obtain the dimming level as a low level analog voltage by C3 and its associated components.  The LM3914 chip selects one of its outputs depending on the amplitude of the voltage, which turns on one of the LEDs to indicate the speed, and turns on one of the Solid State Relays to control the fan speed.  The LEDs allow a handy display of the speed.  The top LED (green) shows full power to the fan __ Designed by Ed Cheung

Nokia 7650 LCD Controller -  Despite nobody seems to own the appropriate documentation, it is possible to use the big cheap color LCD displays of the Nokia series 60 cell phones for home brew projects.  I don't even have the docs and it was a rough and painful way, but now it works

Non-Dimmable Fluorescent Ballast -  Efficient fluorescent lamps and magnetic ballasts have been the standard lighting fixture in commercial and industrial lighting for many years.  Several lamp types, rapid start, high output, and others are available for cost effective and special applications.  This user guide covers operation and development details of the non-dimmable version of our fluorescent ballast for operating a variety of lamps that are available today.   __ Designed by AT89RFD-10 / EVLB002

Notch Filter Autotunes for Audio Applications -  24-Jun-10 EDN-Design Ideas Tracking notch filters find use in harmonic-distortion analyzers; they also can remove heterodyne noise from ham-radio systems.  A conventional tracking switched-capacitor notch filter relies on a bandpass filter, a voltage-to-frequency converter, and a notch filter to track the incoming signal and remove undesired tones.  The bandpass filter in these circuits sometimes adjusts to the wrong frequency, meaning that the undesired tone would have no attenuation __ Circuit Design by John R Ambrose, Mixed Signal Integration, San Jose, CA

Nothing Box -  The nothing box is a set of nine relaxation oscillators.  It blinks random patterns and looks cool.  When the voltage on the capacitors charge to 65 volts, the neon gas ionizes and discharges the capacitors to 55 volts.  The frequency can be simply calculated from the exponential RC function, assuming that the discharge time is neglible to the charging time.   __ Designed by Michael Ellis

Notoof Remote Telemetry Device! -  This PIC project permits five analogue signals to be acquired (to ten bits resolution) and transmitted to a remote computer.  As well as a conventional serial output, the PIC generates an FSK signal that can be conveyed through almost any audio channel.  The FSK output is used in this project to illustrate data transfer using an FM transmitter.   __ Contact: Karen's Microprocessor Projects

Novel controls AC power -  01/07/99 EDN-Design Ideas (Several Circuits in File.  Scroll to find this one)  The simple and inexpensive power-control circuit in Figure 1 uses a readily available fan regulator with built-in phase control.  Such fan regulators are limited to approximately 100W.  The circuit in Figure 1 adds two SCRs and a few components Page includes several designs.   __ Circuit Design by Narendra Paranjape, Tata Chemicals Ltd, Mithapur, India

Nu-based stepper Motor drive -  A nifty (single-IC!) circuit to drive the bipolar stepper motor that's a part of floppy drives:  __ Designed by Wilf Rigter

NuStepper -  Uses just a single IC ('though not one you're likely to have in your "parts box") to give you reversible motor drive __ Designed by Wilf Rigter

Oatley DC Motor Windmill -  Based on a 300watt 24v DC scoota motor, this little windmill would work well if I could boost the output voltage.  

Old idea, new twist-Magic Lamp -  You have probably seen "magic lamp" circuits in which an ordinary incandescent bulb is lit by a match.  These circuits rely on a hidden temperature or light sensor and are not particularly interesting.  I decided to make a magic lamp,  __ Contact: Charles Wenzel of Wenzel Associates, Inc.

On and Off Programmable Controller for 3-Phase Motor -  Automatic on/off controller for a 3-phase electric motor can be made with a programmable time switch.  In this case a maximum of eight time durations can be programmed.  The system has two...__ Electronics Projects for You

On/Off Motor Control with Brake -  Modern electronic speed controllers (ESCs) are very efficient, but they still have some drawbacks.  An inexpensive ESC with two IRFZ40 MOSFETs has an on-resistance of 14 milliOhm.  At 20A current, this means a voltage drop of 0.28V, and a power loss of 5.6W.  Furthermore, to build an ESC with a brake generally requires an expensive P-channel MOSFET __ Designed by Stefan Vorketter

On/Off Motor Controller with Brake -  The circuit for the controller begins with a buffer, consisting of R1, R2, R3, and Z1A, which isolates the receiver from the rest of the circuit and makes operation of the circuit independent of the exact signal levels from the receiver.   __ Designed by Stefan Vorketter

One Cell Flashes White LED -  12/11/03 EDN-Design Ideas Many portable appliances and other products that must operate from a single cell are restricted to working at very low voltages.  It is thus difficult to drive white LEDs that typically have a forward voltage of 3 to 5V.  The ability __ Circuit Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK

One component drives stepper Motor -  The extremely simple circuit in Fig 1 drives a stepper motor directly from 12V ac , 60 Hz power supply.  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.  In this case only one 6.8uF non polarity capacitor is needed.   __ Contact: info @ wzmicro.com

One FET controls LED array -  04/12/01 EDN-Design Ideas White-LED backlights are gaining acceptance because they offer higher reliability and simpler drive circuitry than backlights based on CCFL  (cold-cathode-fluorescent-lamp] and EL  (electroluminescent] technology.  As a result, white-LED backlights are increasingly common in PDAs  (personal digital assistants], cell phones, digital cameras, and other portable devices.  A design __ Circuit Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA

One processor pin controls on/off function -  04/29/04  EDN-Design Ideas A recent Design Ideasprompted me to offer the simpler solution that I used in a recent project   (Reference 1].  We needed a momentary power switch with processor supervision.  This supervision would allow the processor to delay a powe __ Circuit Design by Michael Sirkis, Radio Systems, Logan Township, NJ

One switch controls digital potentiometer -  09/19/02  EDN-Design Ideas This design idea     is an evolution and simplification of another (Figure 1, Reference 1].  Replacing the three inverted-input NOR gates with their logical equivalents, positive-input NAND gates, makes these three gate symbols consistent __ Circuit Design by Jim Bach, Delphi Delco Electronics Systems, Kokomo, IN

One Wire Barometer -  By using a dual voltage supply, instrument precision and/or instrument range can be improved without adding significantly to the parts count.   __ Designed by A.G. Miller

One wire brings power & data to LCD Module -  01/27/14EDN-Design Ideas If you need to connect a small remote LCD display, or your C has run out of I/O pins, heres a good, cheap solutionEmbedded systems frequently use HD44780type LCD displays as it is considered the most popular alphanumeric display controller.  The interface comprises at least 14 pins: eight for data, three for control   (EN, WR, RS), two for power supply   (Vdd, Vss), and one for contrast   (Vre).  Configured in 8bit mode, it requires at least 10 I/O lines   (D0D7, EN, RS).  Configured in 4bit mode, it requires at least six I/O lines   (D4D7, EN, RS) __ Circuit Design by Benabadji Noureddine

One wire controls LCD Module -  EDN-Design Ideas 03/20/2017    This one-wire LCD interface DI generates all the signals required to control the ubiquitous character display __ Circuit Design by Rex Niven

One-transistor FM Transmitter -  A truly minimalist circuit.  Performance is relatively poor and stability is a problem.  Q1 modulates the signal and acts as an oscillator.  L1 and C5 determine the frequency.  Decrease C5 for a higher frequency and vice-versa.  

One-Watt White LED Night Light -  As many of you know, I have a pet peeve with poorly made LED night lights.  Often, the light from the LED quickly fades, so within months, the light is useless.  I have posted several versions of modified night lights using higher quality components.  This circuit is yet another version, which produces much more light than those other designs. . . . Hobby Circuit designed by David A. Johnson P.E.-November, 2008

One-Wire Network Controls Remote SPI Peripherals -  09/04/08  EDN-Design Ideas This circuit controls a remote LED display by the 1-wire network through an SPI-compatible display controller __ Circuit Design by Michael Petersen, Maxim Integrated Products, Colorado Springs, CO

One-Wire Relay Control -  schematic only, no circuit description included __ Designed by Simon Atkin

One-Wire Satellite Position Controller -  After finally completing the 1-wire hub project I had time to build a mount for my Triax prime focus satellite dish.  I had also earlier bought two 18" Geotrack Dish Actuators and now needed a method of controlling them remotely from a computer.  So I had the bright idea of using 1-wire devices to control the process of switching the motor supplies and counting the pulses from the actuator sensor __ Designed by Simon Atkin

On-Off Temperature Control -  This circuit controls a load (in this case a dc brushless fan) based on a temperature compared with a setpoint. THe transduced is a diode in the forward polarization regime. In fact when forward biased, the forward voltage drop accross a diode has a temperature dependance, in particular has a negative linear(ish) slope __ Contact: Jonathan Filippi

Op Amp based PID Controller with SPICE simulation -  We've all heard about the wonders of the PID controller, bringing a system's outputtemperature, velocity, lightto its desired set point quickly and accurately.  But now, your boss says okay, design one for us.  Although there's a number of ways to do it, the circuit above nicely separates the three terms into three individual op amp circuits.

Open-loop power supply Delivers as much as 1W -  01/18/01 EDN-Design Ideas For VCRs, TVs, and other equipment that requires a standby mode, you must supply power to a P when other components are asleep to receive and interpret any wake-up signal from the remote control or from the broadcasting company.  These types __ Circuit Design by Christophe Basso, On Semiconductor, Toulouse, Cedex, France

Operates at voltages as high as 540V ac -  08/26/10 EDN-Design Ideas Reducing dc bus voltage reduces costs and lets you use standard dc power circuits.    __ Circuit Design by Vipin Bothra and John Lo Giudice, STMicroelectronics

Optical Filter using Color Film Negative -  This isnt an electronic circuit but the file shows the curve for an optical filter made from exposed color film.  The material blocks most visible light but is very transparent to 880nM infrared light.  Kodak 100ASA is exposed to "cool white" fluorescent light for about 5 seconds . . . Hobby Circuit designed by David A. Johnson P.E.-January, 1998

Optical Remote On/Off Switch -  First published on: 1-10-2006 Using this optical remote control, you can switch on/off any electrical or electronic load.  Like any remote control system, it has a mini transmitter unit (Fig.1) and...__ Electronics Projects for You

Optically isolated stepper Motor controller -  These are some very high-level instructions for building the Opto-Isolated Stepper Motor Controller. Not really a lot to say. Most of the construction is self-explanatory using the PCB artwork, the overlay, and the schematic. Note that the pad for pin 1 on ICs and such are square to help in proper placement. All ICs on the board are NOT oriented the same way, so pay attention. __ Contact: wrb @ cbnews . att.com

Optically isolated TRIAC driver -  One simple way of isolating the two parts of the circuit is shown below.  If a high intensity red led is used in the circuit below, the TRIAC can be switched using a current as low as mA.  This means that the circuit can be connected directly to the output of an op.  amp.  or even a CMOS logic chip.   __ Designed by David Hoult

Optimizing AC Performance in an 18-bit, 250 kSPS, PulSAR Measurement  -  Using the evaluation board software, the FFT data was then captured and analyzed.  The software analysis is part of the evaluation board software, which allows the user to capture and analyze ac or dc performance.  In addition to ac performance, the evaluation board software also allows users to analyze the waveform data and create a histogram for the measured input signal.  , Circuit Evaluation and Test __ Analog Devices from the Lab

Optimizing Digital Motor Control Libraries -  Small electromechanical drives include solenoid drives, single direction DC, bi-directional DC, or brushless DC systems and are typically sized according to their frame size and power in watts.  Digital controllers, software, and complimentary analog and digital solutions from TI can help solve most drive requirements.   __ Designed by Texas Instruments App Notes, 15-Mar-07

Optoelectronic position control simplifies Motor Movements -  29-Apr-04 EDN-Design Ideas The optoelectronic technique for achieving position control provIdeas an inexpensive, easy- to-design method of achieving simple, repeatable movement using fixed index points with linear- or rotary-motion components.  The simple, basic design in Figure 1 for sequential position control exploits the quick response time of a power op amp, working in tandem with a pair of photodiodes __ Circuit Design by Marie Rivera, Apex Microtechnology Corp, Tucson, AZ

Opto-Isolated logic level trigger for general strobe applications -  Schematic only, no circuit description.  

Ornamental Flashing LEDs -  This circuit can flash three sets of LEDs with different levels of Flashing.  It can be used as Ornamental displays.  The circuit uses a simple Astable multivibrator built around the popular timer IC NE555.  Resistors R1, R2 and capacitor C1 determines the output frequency.  When the output becomes high, Red LEDs lights first.  When __ Designed by D Mohankumar

Oscillator/Reference Oven Temperature Regulation -  The LTC2990 is used to monitor system temperatures, voltages and currents.  Through the I2C serial interface, the device can be configured to measure many combinations of internal temperature, remote temperature, remote voltage, remote current and internal VCC.  The internal 10ppm/C reference minimizes the number of supporting __ Linear Technology/Analog Devices App Note, Mar 16th 2011

OTP C controls Boomer Amplifier -  03/18/99 EDN-Design Ideas NOTE :  Page includes several designs.  Scroll to find this one.  Figure 1 shows a circuit that uses a one-time-programmable (OTP) C in an unusual way.  A COP8SGR7 C uses digital signals to "bit-bang" an LM4835 (dubbed "Boomer" by National) amplifier.  Although the amplifier is designed for potentiometer control, you can modify it to make it a fully digitally controlled part.  Figure 2 shows the flow chart for the control process.   __ Circuit Design by Wallace Ly, National Semiconductor Corp, Santa Clara, CA

Outdoor Lighting Controller -  When you step out of your brightly-lit house into the darkness, it takes a while for your vision to adjust.  A solution to this problem is this outdoor light with automatic switch-off.  As a bonus, it will also make it a little bit easier to find the keyhole when returning late at nightmust register on this site __ Designed by Published in Elecktor July/Aug, 2010

Over-Temperature Micro-Power Alarm -  The circuit is powered for years by a single 3 volt lithium battery.  It sounds an alarm when the temperature exceeds a certain point.  With some minor changes the circuit could also be configured for an under temperature (freeze) alarm.  The circuit uses a . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Overvoltage Regulator with 250V Surge Protection -  The LT4363 surge stopper protects loads from high voltage transients.  It regulates the output during an overvoltage event, such as load dump in vehicles, by controlling the gate of an external N-channel MOSFET.  The output is limited to a safe value allowing the loads to continue functioning.  The LT4363 also monitors the voltage__ Linear Technology/Analog Devices App Note, Jan 16th 2012

Overvoltage Regulator with Low Battery Detection & Output Keep Alive During Shutdown -  The LT4356 surge stopper protects loads from high voltage transients.  It regulates the output during an overvoltage event, such as load dump in automobiles, by controlling the gate of an external N-channel MOSFET.  The output is limited to a safe value thereby allowing the loads to continue functioning.  The LT4356 also monitors__ Linear Technology/Analog Devices App Note, Apr 26th 2010

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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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