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Last Updated: December 01, 2017 03:41 AM

Circuits Designed by Dave Johnson, P.E.

SSR Requires Ultra Low Control CurrentMost solid state relays require at least 5ma and often more input control current, to fully turn on the device.  But such current levels often force battery powered circuits to use excessively large batteries.  The relay hobby circuit shown below demands only 50uA of input current . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

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Speed Controller for DC Motor -  Here is a simple circuit to control the speed of a DC motor.  It can be configured to control the sweep rate of automobiles’ windscreen wiper.  The circuit comprises a timer NE555...__ Electronics Projects for You

Speed Controller for Robot -  The purpose of a motor speed controller is to take a signal representing the demanded speed, and to drive a motor at that speed.  The controller may or may not actually measure the speed of the motor.  If it does, it is called a Feedback Speed Controller or Closed Loop Speed Controller, if not it is called an Open Loop Speed Controller.  Feedback speed control is better, but more complicated, and may not be required for a simple robot design __ Designed by Paul Hill

Speed Controller for Small Cooling Fans -  Small cooling fans are used in some equipment for cooling semiconductor devices.  The circuit given here is of a simple automatic speed controller for a 12V, 0.6W (or 1.2W) cooling fan...__ Electronics Projects for You

SSR Requires Ultra Low Control Current -  Most solid state relays require at least 5ma and often more input control current, to fully turn on the device.  But such current levels often force battery powered circuits to use excessively large batteries.  The relay hobby circuit shown below demands only 50uA of input current . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Stealth-mode LED controls itself -  05/25/06  EDN-Design Ideas High-efficiency LED doubles as a light detector- Since the LED’s invention more than 30 years ago, its emission efficiency has steadily increased, and,although it may surprise you, the increased conversion efficiency works i __ Circuit Design by Howard Myers, Greensboro, NC

Step Down Rectifier Makes a Simple Circuit DC Power Supply -  04/09/98 EDN-Design Feature(Several circuits included.  Scrol to find this one) A simple and useful nonisolated rectifier features voltage step-down operation, acceptable Class A line-current harmonics, inherent short-circuit protection, and, optionally __ Circuit Design by Nathan O Sokal, Design Automation Inc, K Kit Sum, Consultant, and David C Hamill, Surrey Space Centre

Step Up/Step Down Converter Takes 2 to 16V Inputs -  07/16/98 EDN-Design Ideas (Several circuits in this file.  Scroll to find this one)  The circuit in Figure 1 is a low-cost step-up/step-down dc/dc converter.  By definition, its input can range above and below the regulated voltage.  The circuit includes a simple switchmode boost converter (IC1) that contains a comparator normally used to detect low battery voltage.    __ Circuit Design by Lucian Brodogna and  Luca Vasalli/ Maximin Integrated Products, Milan Italy

Step up/step-down current-source charges batteries -  06/06/96  EDN-Design Ideas For battery charging, the highly efficient step-down (buck] configuration is usually the topology of choice.  However, a different approach is necessary if the following conditions prevailThe supply voltage is less than the battery  __ Circuit Design by Michael Keagy, Maxim Integrated Products, Sunnyvale, CA

Stepdown Converter Uses a Ceramic Output Capacitor -  12/31/69 EDN-Design Ideas Many stepdown (buck) dc/dc-converter ICs incorporate a voltage-mode-control algorithm.  As a result, for stable operation in continuous-conduction mode, the application circuit's output capacitor is normally a high-ESR tantalum type for two reasons.  The portion of output ripple due to ESR provIdeas the current-mode signal that's necessary for cycle-to-cycle stability.  In the frequency domain, this capacitor also provIdeas a zero that cancels a pole in the buck converter's second-order LC filter, thereby shifting operation back to the stable region by reducing the ripple's phase shift to less than 90°.    __ Circuit Design by Karl R Volk, Maxim Integrated Products, Sunnyvale, CA

Stepper Controller from Recycled Materials -  I am 13 I have always wanted to build a cnc machine but because inexpensive parts are hard to find in Canada I have had trouble trying to build a decent cnc controller.  The purpose if this Instructable is to show that anyone can build a cnc __ Designed by Radio LocMan

Stepper Motor Connections -  Stepper motors are available in many different models.  One of the main differences is the number of connections.  That can vary from 4 to 8 wires or terminals.  The oldest models, for the unipolar drives have 5 or 6 leads.  

Stepper Motor Control -  A simple, low-cost hardwired step per motor control circuit that can be used in low-power applications, such as moving toys etc is presented here.  The circuit comprises a 555 timer IC configured as an astable multivibrator with approx.1Hz frequency.  The frequency is determined from the following relationship: Frequency = 1/T = 1.45/(RA + 2RB)C

Stepper Motor Controller -  Use one of those surplus motors with these cheap and easy-to-build controller.__ SiliconChip

Stepper Motor Controller -  The direction of rotation is determined by the FORWARD and REVERSE switches and the motor does not take any current when a switch is not pressed.  __ 555-Timer

Stepper Motor Controller -  I found this circuit in my files.  I don't know where it came from, but it looks like I photocopied it from somewhere years ago.  I have been told that it came from "The Robot Builder's Bonanza", by Gordan McComb.  Anyway, I thought that it should be fairly useful, so I decided to post it here.  The circuit is very simple and inexpensive.  This is good thing because most commercial stepper motor controller ICs are quite expensive.  This circuit is built from standard components and can easily be adapted to be controlled by a computer.  If you use cheap surplus transistors and stepper motor, the price of the circuit can be kept to under $10. __ Contact: Aaron Cake

Stepper Motor Controller -  The circuit shown above can be used to control a unipolar stepper motor which has FOUR coils (I’ve swiped it off an old fax machine).  The above circuit can be for a motor current of up to about 500mA per winding with suitable heat sinks for the SL100.  For higher currents power transistors like 2N3055 can be used as darlington pair along with SL100.  The diodes are used to protect the transistor from transients.

Stepper Motor Controller -  Stepper motor driver that will allow you to precisely control a unipolar stepper motor through your computer's parallel port.  With a stepper motor you can build a lot of interesting gadgets such as robots, elevator, PCB drilling mill, camera panning system, automatic fish feeder, etc.  If you have never worked with stepper motors before you will surely have a lot of fun with this project.  __ 555-Timer

Stepper Motor controller -  On these pages, I will introduce a control circuit for stepper motor.  The software of this project is adapted to Embedded Systems (Lab13) for 2002 of Cleveland State University.  PIC16F84A __ Designed by Seiichi Inoue

Stepper Motor Controller Connection Diagrams -  Four-Wire Connection The ULN2003 / MC1413 is a 7-bit 50V 500mA TTL-input NPN darlington driver.  This is more than adequate to control a four phase unipolar stepper motor such as the KP4M4-002

Stepper Motor Driver -  A stepper motor has four coils.  The direction of rotation (clockwise or anti-clockwise) depends on the order in which the currents supplied to the coils are switched on.  If you use the motors type 55SI-25 DAYA, having a connector as shown below,  __ Designed by © David Hoult

Stepper Motor Driver using L298 & L297 -  This Stepper motor controller uses the L297 and L298N driver combination; it can be used as stand alone or controlled by microcontroller.  It is designed to accept step pulses at up to 25, 000 per second.  An on-board step pulse generator can be used if desired (40-650 pps range).  Single supply operation is standard __ Designed by www.wzmicro.com

Stepper Motor Driver using TEA3718/3717 -  The stepper motor driver circuit is using a pair of TEA3718/3717 to drive the stepper motor in bipolar chopper configuration.  The U3 555 timer provides the clock pulse.  The U1 and U2 form a two-direction TTL full step generator.  If only one direction is needed then the circuit below can be used.   __ Contact: info @ wzmicro.com

Stepper Motor driver with PBM3960 & TEA3721 -  This Microstepping motor driver offers a short cut to get familiar with microstepping.  It is a complete system to driver the bipolar stepper motor in micro-stepping mode as well as the half step and full step modes.  This board is built around the Ericsson PBM3960 (NJR NJU39610) microstepping controller and TEA3718 stepper motor driver __ Contact: info @ wzmicro.com

Stepper Motor Experiment -  Stepper motors are most commonly controlled by microprocessors or custom controller ICs and the current is often switched by stepper motor driver ICs or power transistors.  Precise motion is possible but the complexity usually lands the hobbyist's stepper motors in the "maybe someday" parts bin.  But steppers may be used for a variety of applications without complex circuitry or programming.  At first glance the stepper motor looks a bit intimidating since there are at least four wires and often there are six.  Most steppers have two independent windings and some are center-tapped, hence the four or six wires.  A quick ohmmeter check will determine which wires belong together and the center-tap may be identified by measuring the resistance between the wires; the center-tap will measure 1/2 the total winding resistance to either end of the coil.  Tie the wires that belong together in a knot and tie another knot in the center-tap wire for easy identification later.  Stepper motors have become quite abundant and are available in all shapes and sizes from many surplus dealers.  Experimenters can also salvage excellent steppers from old office and computer equipment.   __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Stepper Motor Generator -  Stepper motors are a subject that keeps recurring.  This little circuit changes a clock signal (from a square wave generator) into signals with a 90-degree phase difference, which are required to drive the stepper motor windings.  The price we pay for the simplicity is that the frequency is reduced by a factor of four.  This

Stepper Motor Interface -  M1 is a stepper taken from an old disk drive.  There are five pins, i.  e.  , common, coil 1, 2, 3 and 4.  Resistance measured between common pin and each coil is about 75 Ohms.  Driving current for each coil is then needed about 60mA at +5V supply.  A darlington transistor array, ULN2003 is used to increase driving capacity of the 2051 chip __ Designed by Wichit Sirichote

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

Stepper Motor used as encoder -  It is quite possible to use a small stepper motor as a rotary encoder.  Here's a circuit I knocked up when, I was designing automatic welding machine controls, as a feasibility study.  In fact the idea was never used, so I never designed logic to process the signals.  It uses a bipolar stepper (with two windings, or 'phases').  Only one phase of the stepper is shown hereyou will need to duplicate this circuit for the second winding.   __ Designed by Richard Torrens

Stepper Motor Voltage Doubler -  Double the voltage from a stepper motor using two bridge rectifiers.   __ Designed by REUK-Renewable Energy UK website

Stepper-motor Motion controller & driver fit into a CPLD/FPGA -  06/21/07  EDN-Design Ideas A CPLD or FPGA can be a home for a stepper-motor motion controller and driver __ Circuit Design by Stephan Roche, Santa Rosa, CA

Stepping Motor Controller -  Intelligent stepper motor controller with PIC16F84.  It can be controlled with PC that conncted with RS-232C.  And it can also set up acceleration value, maximum velocity and drive method.   __ Designed by The Electronic Lives Manufacturing-presented Chan

Step-Up Regualtor Uses Only Two Gain Device -  01/05/95 EDN-Design Ideas The step-up regulator in Fig 1 varies the negative bias of its switching oscillator in response to an error signal from an output-voltage comparator.  The circuit uses no transformers, only inductors.  The regulator accepts 8 to 12.5V dc and outputs 18V dc.  Its efficiency measures 77%.  The circuit's oscillator switch, an enhancement-mode MOSFET (Q1), achieves high switching speeds and efficiency.   __ Circuit Design by Eugene E Mayle, RL Drake Co, Franklin, OH

Step-Up Supply Charges Battery While Serving LoA - D -  06/08/95 EDN-Design Ideas The circuit in Fig 1 supports portable applications in which a microprocessor controls battery charging.  Step-up switching regulator IC1 boosts VIN (5V]to supply a combination of charging and load current.  (Note that the 5V source  __ Circuit Design by Dana Davis, Maxim Integrated Products, Sunnyvale, CA

Stereo jack adds no-cost power/logic control -  EDN-Design Ideas – April 15, 1999    [ NOTE : File has multiple design, scroll for this one.]  Many battery-powered devices use peripherals that require only two conductors to complete their interfaces.  You can use stereo phone jacks and monaural plugs to perform power- or logic-control functions in addition to completing their required I/O connections.  Monaural plugs short-circuit the ring and sleeve of stereo jacks.  You can place the ring connector, normally considered a redundant ground return, into service as an spst switch.   __ Circuit Design by Gary O’Neil, IBM Microelectronics, Research Triangle Park, NC

Stereo Test Tone Generator -  This circuit produces two audio frequency sine waves with different frequencies but equal amplitudes.  It can be used for testing a variety of stereo audio equipment.  The circuit was originally developed the purpose of aligning an FM Stereo Modulator, like the type used in low power FM stereo transmitters.  Two tone outputs are available, the low tone has a secondary output that is 180 degrees out of phase with the primary output.  The circuit is also handy for testing computer sound card inputs.  A variety of waveform configurations can be produced by plugging a stereo audio patch cord into the four output jacks. __ Designed by G. Forrest Cook

Stereo Tone Control Based LM1036N -  The following circuit is a Stereo Tone Control Circuit which build based LM1036N.   The LM1036 works as a DC controlled tone (bass/treble), volume and balance circuit for stereo audio purposes in car radio, TV and audio systems.  An extra control input will allow loudness compensation to be simply effected.  Four control inputs provide control of the bass, treble, balance and volume capabilities through application of DC voltages from a remote control system or, additionally, from four potentiometers that might be biased from a zener regulated supply given on the circuit.  Each tone response is defined by a single capacitor selected to give the desired characteristic.

Stereo Tone Control with Transistor -  Above diagram is the circuit diagram of stereo tone control which also available to buy in kit, you could possibly look for the kit at electronic part store close to your location.  The tone control require 12v of power supply to work.

Stereo Width Controllers -  Sometimes, for a variety of reasons, it would be nice to vary the width of the 'sound stage' when listening to stereo recordings.  Although technically this is anything but hi-fi, it is a useful addition to PC speakers, or even for the music centre in the listening room.   __ Designed by Rod Elliott  ESP

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