Safe Hot Swapping using the LTC1421 - DN139  Design Notes (Linear Technology) (app note added 2/06)

Scheme Adds Sequencing and Shutdown Control to Regulator - 10/30/03, EDN-Design Ideas:  Modern microprocessoror FP-GA-based circuits require separate and independent power-supply voltages for the core and the I/O circuits. Some devices require stringent control of the turn-on characteristics and sequencing of these multiple power supplies to avoid internal parasitic current flows and consequent latch-ups.....(design idea added 1/05)

Secondary Side Dual Output Controller Tightly Regulates Two Isolated Outputs - DN1000  Design Notes (Linear Technology)  (app note added 1/06)

Self Powered Solar Box Furnace - (schematic / circuit design added 9/02)

Sensitive Remote Control Tester - (electronic Circuit / Schematic added 10/04)

Sensored BLDC Motor Control using DSPic30f2010 - Microchip Application Note Published 23-Jun-05  (app note added 6/06)

Sensorless BLDC Motor Control using DSPic30f2010 Chinese - Microchip Application Note Published 27-Jul-05  (app note added 6/06)

Sequencer controls power supplies' turn on and turn off order - 01/18/07, EDN-Design Ideas:  (design idea added 05/07)   Two low-cost ICs and a few passive components prevent disorderly shutdown.

Sequential State Machine Aids in Automatic Control - 09/02/04, EDN-Design Ideas:  Creating a sequential state machine is a common approach for automatic-control design. The method finds wide use for controlling sequential processes in industry, robotics, and measuring. The concept of a state machine is simple: A number of states describe a process under control; each state.....(design idea added 1/05)

Serial Infrared Remote Controller - a simple, cheap device that can be connected to any serial port to control most components that have infrared remote controls, includes schematics for receiver and transmitter (added 4/02)

Serial Servo Motor Controller - (circuit / schematic design added 6/06)

Serial-driven IR remote controller - This paper describes a serial infrared transmitter (SIT)  capable of  generating  the infrared codes used by most current equipment that incorporates an infrared remote control.  It is operated by a computer    through  an  asynchronous  communications port.  Driver software....(electronic design added 6/07)

Server Power Supply <600W - (application / block diagram added 6/07)

Servo Circuit - (Circuit added 10/06)

Servo Control of a DC Brush Motor - Microchip Application Note Published 26-Aug-97  (app note added 2/06)

Servo Pulse to Dual H-Bridge - interface performs vital control functions needed for propulsion and steering of a “fighting robot”. (added 7/03)

Servo Slew Rate Control - A circuit that limits the rate of change of a signal; a feature of this design is that the positive and negative rates can be different. (added 5/02)

Several stepper motor Control circuits - (circuit / schematic design added 6/06)

Short DC Power Line Pulses Afford Remote Control - 10/25/01, EDN-Design Ideas:  If you face the challenge of adding a second, independently controlled light source to an existing ceiling lamp controlled by a wall switch, you may find that stringing a second power line is impossible. First, you can replace the wall switch by the circuit in Figure 1. Pushing the on switch S1 or S2.....(design idea added 1/05)

Simple µC acts as dedicated motor control  - 09/11/98, EDN-Design Ideas:  (design idea added 6/06)

Simple 4-CH Remote Control - You can construct your own long range infrared (IR) wireless remote using Motorola's MC145026 emitter and MC145027 detector chips. With your remote you can control devices up to 20 feet (7 meters) away. It operates similiarly to a TV remote. You just point the emitter at the detector, push a transmit button. The detector then interprets your data signal. You can use this circuit to remotely turn on/off devices (like a motors, relays, home appliances). ….(electronic schematic added 11/08)

Simple circuit allows long PWM soft starts - 02/01/07, EDN-Design Ideas:  (design idea added 05/07)   Enhance timing accuracy of a switching regulator's start-up ramp.

Simple Circuit Controls Stepper Motors - 01/08/04, EDN-Design Ideas:  Stepper motors are useful in many consumer, industrial, and military applications. Some, such as personal-transportation systems, require precise speed control. Stepper-motor controllers can be simple (Figure 1), but they require a variable-frequency square wave for the clock input.....(design idea added 1/05)

Simple Circuit Provides Motor Feed Control - 07/25/02, EDN-Design Ideas:    Because we needed a small grinding machine, we modified an old milling machine that lacked a control system. The table of the grinding machine needed only to move back and forth with adjustable feed. Using an existing dc servoamplifier, a servo motor, and limit switches, we devised the circuit shown in Figure 1.....(design idea added 1/05)

Simple DC motor PWM speed control - ….(electronic schematic added 08/08)

Simple ESC - with optoisolated input (schematic added 10/06)

Simple Infrared Remote Control - (circuit / schematic design added 6/06)

Simple Remote Control Tester - (electronic circuit added 10/05)

Simple Sensitive Remote Control Tester - (electronic Circuit / Schematic added 10/04)

Simple servo controller - This cicuit allows you to test a servo. The angle of the servo can be set by means of the 10k potmeter. Perhaps you will not be able to reach all positions with this circuit. Playing with other...

Simple stepper motor controller - This design allows for very precise control of the motor: by proper pulsing, it can be turned in very accurate steps of set degree increments (for example, two-degree increments, half-degree increments, etc.). They are used in printers, disk drives, and other devices where precise positioning of the motor is necessary. There are two basic types of stepper motors, unipolar steppers and bipolar steppers....(circuit added 07/08)

Simple Sump Pump Controller - Having a reliable system to pump out a sump pit is essential as mistakes and failures can lead to serious flooding and enormous expense. In our article Sump Pump Control System we introduced a selection of electronic solutions to the following problems….(electronic schematic added 08/08)

Simple Two Speed Contactor DC Motor Controller - The simplest of all motor controllers (besides a straight on/off switch) is the contactor controller. Aaron designed this contactor controller for use in his...

Simple two transistor circuit lights LEDs - 04/09/09, EDN-Design Ideas:  (design idea added 08/09)

Single FET Controls LED Array - 04/12/01, EDN-Design Ideas:  (design idea added 6/06)

Single Phase Electronic Starter - Anovel Single-phase electronic starter circuit meant for 0.5 HP and 1 HP motors, is presented. It incorporates both over-load ….Circuit / schematic (added 02/05)

Single pin controls relay intermittent buzzer and status LED - 04/09/09, EDN- Design Ideas -  One pin controls relay, buzzer, and status LED for control applications.....(design idea added 08/09)

Single Processor Pin Controls On/Off Function - 04/29/04, EDN-Design Ideas:  A recent Design Idea prompted 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 power-down request from a press of the power switch until all routines exited properly.....(design idea added 1/05)

Single Switch Controls digital potentiometer #2 - 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 with the fourth, which....

Single-Phase Induction Motor Drive - (application / block diagram added 6/07)

Sinusoidal Control of Pmsm Motors with DSPic30f DSc - Microchip Application Note Published 21-Dec-05  (app note added 2/06)

Small Motor Speed Regulator  - Reverse engineered circuit diagram of a motor speed regulator out of a portable tape recorder containing a single motor for all functions. This circuit works amazingly well, keeping the motor speed constant regardless of shaft load and battery voltage. (added 2/05)

Smart Switch Cuts Transformer Turnon Current  - 04/23/98, EDN-Design Ideas:  [Note:  File contains multiple circuits scroll to find this circuit.]  Piezoelectric buzzers, such as the Murata (Smyrna, GA)PKB5-3A in Figure 1, make excellent alarms. They're compact, lightweight, efficient, and reliable. However, a piezo alarmr.....(design idea added 11/05)

SMS remote control v2.2 - Control up to 8 devices ( On-Off  or Reset) by sending a SMS message from  any mobile phone, to  ericsson  T10s, of our circuit.….(design added 03/09)

Soft Button Type Motor Direction Controller - This circuit can control a small DC motor, like the one in a tape recorder. When both the points A & B are "HIGH" Q1 and Q2 are in saturation. Hence the bases of Q3 to Q6 are grounded. Hence Q3,Q5 are OFF and Q4,Q6 are ON . The voltages at both the motor terminals is the same and hence the motor is OFF. Similarly when both A and B are "LOW" the motor is OFF.....  (added 10/05)

Soft Start Circuit for Power Amps - Designed for (large) toroidal transformers, limit the inrush current to a sensible value.  (schematic / circuit design added 9/02)

Soft Start Controller is Gentle on Loads - 11/22/01, EDN-Design Ideas:  The control circuit in Figure 1 senses a given load and automatically soft-starts the load by synchronously adjusting the power to that load. You can also manually adjust the power delivered to the load by controlling the phase angle of the line voltage across the load. The phase-angle adjustment for every ac half cycle covers0 to 180.....(design idea added 4/03)

Soft-Start Circuit for Power Amps - This circuit requires experience with mains wiring. Do not attempt construction unless experienced and capable. Death or serious injury may result from incorrect wiring…(electronic circuit added 4/05)

Solar array controller needs no multiplier to maximize power - 12/05/08, EDN-Design Ideas:  -  Relying on the logarithmic behavior of transistor junctions to calculate power, this controller operates a photovoltaic array at its maximum power point.....(design idea added 08/09)

Solar Car Array Controller Schematic - (electronic circuit added 7/03)

Solar Car Brake Controller Schematic - (electronic circuit added 7/03)

Solar Car Display Controller Schematic - (electronic circuit added 7/03)

Solar Powered Motor Runs on 10 Na - 03/18/04, EDN-Design Ideas:  Designs for solar-powered applications with low-duty-cycle requirements can often rely on capacitors for energy storage in place of less reliable batteries. Typical applications include solar positioning, telemetry transmitters, chemical pumps, data loggers, and solar-powered toys.....(design idea added 11/05)

Solid State Relay Requires only 50uA Drive Current - This circuit demands a control current that is 100 times smaller than that needed by a typical optically isolated solid state relays. It is ideal for battery-powered systems. Using a combination of a high current TRIAC and a very sensitive low current SCR, the circuit can control about 600 watts of power to load while providing full isolation and transient protection. Published in Electronic Design, Dec 2, 1996. ….(designed by David A. Johnson)

SOT-23 Smbus Fan Speed Controller Extends Battery Life and Reduces Noise - DN238  Design Notes (Linear Technology) (app note added 1/06)

Sound Controlled Flip Flop - Described here is a very inexpensive solution to many phono-controlled applications like remote switching on, for instance, or activating a camera, tape recorder, burglar alarms, toys, etc. The circuit given here employs a condenser microphone as the pick-up. A two-stage amplifier built around a quad op-amp IC LM324 offers a good gain to enable sound pick-up upto four metres. ….  (added 10/05)

Speed Control - Speed Control with aSwitching rate of 15KHz (circuit added 10/06)

Speed control based on the ZN409 - Speed control based on the ZN409

Speed Control for RC Car - DC motor PWM controller that takes the1ms to2ms pulse from the RC receiver and converts it into a PWM train at1Khz (added 6/06)

Speed Control of 3-Phase Induction Motor using PIC18 Microcontrollers - Microchip Application Note Published 2-Jul-02  (app note added 2/06)

Speed Control with Reverse - (Schematic added 10/06)

Speed Controller - There are many ways of producing a PWM wave form, it can be done with PIC’s, 555 timers, Nand gates and schmitt triggers, but I’ve taken the easy way out by using a custom made PWM motor controller (in kit form) and modifying it (slightly). The kit in question is from Maplin part no (VF59P). Below ....(circuit added 10/06)

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.... (diagram added 10/06)

Speed Measurement and Control with the AD2S83, Silicon Tachogenerator - AN-236 Analog Devices Application Notes  (app note added 6/06)

Stepdown converter uses a ceramic output capacitor - 06/07/01, EDN-Design Ideas:.....(design idea added 7/03)

Stepper Control - ….(circuit design added 07/08/09)

Stepper Motor Control using the PIC16f684 - Microchip Application Note Published 23-Feb-04  (app note added 2/06)

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. ….(electronic schematic added 11/08)

Stepper motor Controller (Aaron Cake) - (electronic circuit added 4/05)

Stepper Motor controller (interg) - There are many kind of stepper motors. Unipolar type, Bipolar type, Single-phase type, Multi-phase type. Single-phase stepper motor….(electronic circuit added 08/08/08).

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 KP4M4-001. ….(circuit design added 11/08)

Stepper Motor Drive - (application / block diagram added 6/07)

Stepper Motor Driver (74194) - Probably the simplest, reversible drive circuit is the H-Bridge. Some BEAMbots use H-bridge motor drivers; many more use an H-bridge variant of some sort. Here's a simple….(design added 11/08)

Stepper Motor Microstepping with PIC18c452 - Microchip Application Note Published 21-Mar-02  (app note added 2/06)

Stepper motor motion controller and 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.....(design idea added 9/08)

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.  (added 10/05)

Stepping Motors Fundamentals - Microchip Application Note Published 23-Feb-04  (app note added 2/06)

Stereo Jack Adds No Cost Power/Logic Control - 04/15/99, EDN-Design Ideas:  [Note:  File contains multiple circuits.  Scroll to find 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 poweror logic-control functions in addition to.....(design idea added 6/06)

Strobe Controller - Simple controller for professional stroboscopes, adjust the flash rate in1.15 Hz range (added 4/02)

Subscriber Line Card for Central Office Telephone Switching Equipment - National Semiconductor Application Note  (app note added 6/06)

Subscriber Line Card in a Distributed Control Switching System - National Semiconductor Application Note  (app note added 6/06)

Sunrise Lamp - In this circuit, a 120VAC lamp is slowly illuminated over a approximate 20 minute period. The bridge rectifier supplies 120 DC to the MOSFET and 60 watt lamp. A 6.2K, 5 watt resistor and zener diode is used to drop the voltage to 12 volts DC for the circuit power. The bridge rectifier should be rated at 200 volts and...(circuit added 05/09)

Super Bright 3v Powered LED Flasher - I have posted several kinds of LED flashers over the years.  This is yet one more flasher, designed to flash any high power LED of any color.  It hits the LED with a 25ms 250ma pulse once every 2 seconds.  This works out to an average current about 3ma.  It is powered by any 3v source.  I suggest two AA cells but a single 3v lithium coin type cell will also work.  With fresh AA cells, the light should flash for about two weeks.  The light flash is very intense and is perfect for any attention getting night time application..... ….(designed by David A. Johnson)

Super Remote - Using a PIC12F683 and a few transistors, it is theoretically possible to boost the power to a standard 433 MHz remote transmitter module. (Note hypothetical image at right).
….(electronic schematic added 08/08)

Super Simple Stepper Motor Controller - (electronic circuit added 10/05)

Switch Debouncer Isolates Input and Output - 04/27/00, EDN-Design Ideas:.....(design idea added 11/05)

Switch Debouncer uses Only One Gate - 05/30/02, EDN-Design Ideas:   The circuit in Figure 1 produces a single debounced pulse each time you press S1. Moreover, the circuit uses only logic power from the remote pull-up resistor, R2. You can use the circuit to detect when a key is pressed in a nonenergized device, such as a device in a system that's just coming up from standby…..(design idea added 11/03)

Switch De-bouncer Using a 555 Taken from Forrest Mims Mini Notebook. - (circuit design added 10/06)

Switched reluctance Motor Drive - (application / block diagram added 6/07)

System monitors multiple temperatures Controls Fan speed - 10/12/00, EDN-Design Ideas:.....(design idea added 7/03)