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  /  (added 1/05)  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....

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)

Sensorless brushless motor control:  Brushless Direct Current (BLDC) motors are increasing in popularity in consumer and industrial electronics because of their compact size, controllability, and high efficiency. For instance, this type of motor can eliminate automotive belts and hydraulic systems for improved functionality and fuel economy. Their compact size is a result of continued improvements in magnets, rendering improvements in efficiency. Additionally, BLDC motor systems are experiencing a reduction in magnetic and electronic costs..... (electronic design added 10/06)

Sequencer controls power supplies' turn-on and turn-off order:  1/18/2007)  EDN Design Ideas  / (added 02/07)    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  /  (added 1/05)  Creating a sequential state machine is a common approach for automatic-control design. The meth-od 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 produces some output signals and advances to the next state according to received input signal....

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)

Servo Circuit:  (Circuit added 10/06)

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  /  (added 1/05)  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 for approximately 1 sec inserts the 12V zener diodes D1 or D2 in series with the ... ...

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

Simple Circuit Controls Stepper Motors:  01/08/04 EDN Design Ideas  /  (added 1/05)  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. The AD9833 low-power DDS (direct-digital-synthesis) IC with an on-chip, 10-bit DAC is ideal for this task, becaus......

Simple Circuit Provides Motor Feed Control:  07)/25/02 EDN Design Ideas  /  (added 1/05)  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....

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 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...

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

Single Phase Electronic Starter:  Circuit / schematic (added 02/05)

Single Processor Pin Controls On/Off Function:  04/29/04 EDN Design Ideas  /  (added 1/05)  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....

Single Switch Controls digital potentiometer #1:  02/07)/02  EDN Design Ideas / (added 6/06)    The control of electronic potentiometers in most today's applications comes from controller-generated signals. However, a significant number of applications exist that require adjustments using manual, front-panel controls. The circuit in Figure 1 uses one IC, one switch, and 10 discrete components. .

Single Switch Controls digital potentiometer #2:  09/19/02  EDN Design Ideas / (added 6/06)   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 was drawn as a positive-input NAND gate. The 74HC132's data sheet describes the device as a quad, two-input NAND gate with hysteresis..

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  /  (added 05/03)

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:  (schematic / circuit design added 9/02)

Soft Start Controller is Gentle on Loads:  11/22/01 EDN Design Ideas  /  (added 4/03)  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 covers 0 to 180....

Soft-Start Circuit for Power Amps:  (electronic circuit added 4/05)

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  /  (added 10/05)  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. The circuit in Figure 1 can run a small pager motor from the output of a small calculator-type solar cell in near......

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 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 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 is the schematic of what it looks like now. The frequency that it runs at has been modified from its original 5k up to 25k, at this frequency the motor can no longer be heard buzzing. To set the frequency measure.... (circuit added 10/06)

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

Stepper motor Controller #4:  (circuit / schematic design added 6/06)

Stepper Motor Controller:  Allows you to precisely control a unipolar stepper motor through your computer (circuit added 9/06)

Stepper Motor Driver :  74194 Inexpensive stepper motor driver that could be used to power slow speed projects on the layout or other hobby applications (added 6/06)

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

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)

Stereo Jack Adds No-Cost Power/Logic Control:  04/15/99 EDN-Design Ideas / (added 6/06) [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 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. A simple wireless transceiver illustrates how you can use stereo jacks for switching with monaural plugs, stereo plugs, or both (Figure 1 and Figure 2). Using the design in Figure 1, you can connect the battery return to the ring of stereo jacks serving one or more I/O devices. The circuit in Figure 2 connects the returns of individual circuits to the ring....

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)

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

System Monitors Multiple Temperatures Controls Fan Speed:  10/12/00 EDN-Design Ideas / (added 7/03)