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OptoCoupled Gate Detects Motor Operation - 02/02/98 EDN Design Ideas: Most applications require redundant system checks to ensure that devices are operating as expected. The circuit in Figure 1 detects when a PWM-controlled servo motor is running. You can monitor the motor-running signal output with a CPU or tie the output to hardware that indicates a fault if the motor is running when it should be off. The motor's output connects to input resistors RIN1 and RIN2. The use of two resistors protects the motor or servo amplifier in the case of a short circuit. RIN1 and RIN2 also serve as current-limiting resistors for the LED in the opto gate, IC2. Design by Malcolm Watts, Wellington Polytechnic, Wellington, New Zealand Optocoupler extends high-side Current-sensorto 1 kV - 03/01/01 EDN Design Ideas: The task of sensing dc current at high voltage is often problematic. Most high-side current-sensing ICs available off the shelf are good only to 30 or 40V. Combining an optocoupler with such an IC yields a sensing circuit in which the only limitation of the high-side voltage is the optocoupler's standoff voltage (Figure 1). Design by Roger Griswold
Optocoupler isolates shift registers - 01/20/00 EDN Design Ideas: Conventional shift registers, such as the 74HC595, require data-, clock-, and strobe-logic signals. The circuit in Figure 1 needs only two logic signals to isolate and control shift-register devices. Design by Jim Hartmann
Optocoupler simplifies power-line Monitoring - 10-Jan-02 EDN Design Ideas: The use of a linear optocoupler and a capacitor-based power supply yields a simple, yet precise power-line-monitoring system. The circuit in Figure 1 converts the 110V-ac power-line voltage to an ac output voltage centered at 2.5V, covering 0 to 5V. The circuit isolates the output signal from the power line Design by Alfredo del Rio and Ana Cao y Paz, University of Vigo, Spain
Optocoupler speed-up also reduces power consumption - EDN Design Ideas: 09/01/2014 Optocouplers tend to be sluggish, unless you have this circuit up your sleeve. Design by Marian Stofka
Optocouplers - Find out more about optocouplers/optoisolators and their uses. __ Designed by REUK-Renewable Energy UK website
Optocouplers are handy for Motor drive - 06/13/02 EDN Design Ideas: Difference amplifier uses digital potentiometers - Figure 1a shows a latching circuit based on an optocoupler, IC1. If the off switch remains closed, pressing the on switch powers the LED in the optocoupler. Thus, the transistor in IC1 turns on. You can now release the on switch, and the transistor remains on. You must adapt the current-limiting resistor, R, to the power-supply voltage and the optocoupler's characteristics Design by Jean-Bernard Guiot, DCS AG, Allschwil, Switzerland
Optocouplers in intrinsic safety applications - EDN Design Ideas: 02/16/2015 Intrinsic safety applications defined in IEC 60079-11 require careful selection of isolation components Design by Avago Tech Note
OptoElectronic Horizontal VBB Seismometer Figures - xxx___ Designer?
Optoelectronic position control simplifies Motor Movements - 29-Apr-04 EDN Design Ideas: The optoelectronic technique for achieving position control provide as 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 Design by Marie Rivera, Apex Microtechnology Corp, Tucson, AZ
Optoisolator Block Occupancy Detector - This page is about a block occupancy detector that uses an optoisolator to electrically separate the track from the detector output. Four variations of the detector are shown. __ Designed by Rob Paisley
Optoisolators Compute Watts & Volt-Amperes - 02/21/08 EDN Design Ideas: Relying on the dynamic conductance of optoisolators' junctions, simple optoisolator bridges compute the watts and volt-amperes of an ac load Design by W Stephen Woodward, Chapel Hill, NC
Phone wire, RJ-11 jacks & optocouplers build a bus - 12/07/04 EDN Design Ideas: Although cutting-edge technology reaps publicity, the real world often runs on modest hardware that's just "good enough" for home automation, alarm systems, and equipment-monitoring applications. Figure 1 shows a low-speed, multidro Design by Ernie Deel, EFD Systems, Marietta, GA
Photoelectric-FET Optocoupler as a Linear Voltage-Controlled Potentiometer - 01/19/12 EDN Design Ideas: The circuit takes advantage of an identical photo-FET as a feedback element. You can use a photoelectric FET as a variable resistor or a potentiometer in combination with a fixed resistor. The H11F3M photoelectric FET has an isolation voltage of 7.5 kV, enabling you to safely control highvoltage circuit parameters. The nonlinear-transfer characteristics of these devices are problematic, however (Figure 1). To correct the nonlinearity, using a simple feedback mechanism as a potentiometer yields a linear response (Figure 2). This circuit uses two photoelectric FETs—one for feedback and the other for applications requiring an isolated potentiometer. You connect the inputs of the two photoelectric FETs in series to ensure the same amount of current for the input LEDs. Design by Sajjad Haidar, University of British Columbia, Vancouver, BC, Canada
RS-232C circuit has galvanic isolation - 04-Feb-99 EDN Design Ideas: NOTE
: File has several circuits, scroll to this one. Galvanic, or electrical, isolation is a well-established technique for noise reduction and works best in computer and industrial systems in which noise can seriously affect data transfer. Isolation removes ground-loop currents and their associated noise voltages from data lines Design by Design Idea byIoan Ciascai, REI Data, Napoca, Romania
RS-232-to-RS-232 Port Powered Optical Isolator - Brochure with schematic in PDF format__ BB Electronic
Signal-Powered Linear Optocoupler Provides Isolated Control Signal - 23-Jul-09 EDN Design Ideas: The circuit in Figure 1 provide as an isolated control voltage, such as 0 to 10V. In the low part of the range, 0V to approximately 2V, the controlled device is off. Therefore, the upper part of the range must be as linear as possible. You can meet this requirement using a linear optocoupler, such as Vishay’s IL300 or Avago Technologies’ HCNR200 or HCNR201. Design by Mitja Rihtarsic, ?kofja Loka, Slovenia
Simple Circuit Measures Optocoupler's Response Time - 09/08/11 EDN Design Ideas: Measure the response speed of optocouplers in order to select matching devices. You can use the circuit in this Design Idea to measure the attack and release times of photoresistor-type optocouplers (Figure 1). Such devices often find use in audio compressors or volume-control circuits. The design uses an oscillating Schmitt trigger with the optocoupler DUT (device under test) in the feedback loop. The photoresistor and resistor R1 form a voltage divider that controls the input of the Schmitt trigger. Design by Peter Demchenko, Vilnius, Lithuania
Smart gate-drive optocoupler with integrated flyback controller - EDN Design Ideas: 03/13/2015 A smart gate-drive optocoupler for FETs & IGBTs is ideal for distributed power supplies, power inverters, motor drives, and more Design by Avago Tech Note
Temperature Sensor Uses I2C Isolator - 6-Jun-96 EDN Design Ideas: You can couple an LM75 digital output-temperature sensor through an isolated I2C (interintegrated circuit] interface (see Reference] as shown in Figure 1. Electrically isolating the sensor allows operation in situations prone to high common-mode voltages; it's also useful in breaking ground loops. IC1 and IC2 comprise a bidirectional isolator Design by Jerry Steele, National Semiconductor, Tucson, AZ
TV/Radio Antenna Cable Galvanic Isolator - A ground loop in your AV system caused by antenna connection or TV cable is very common if you have your computer connected to the same system. This type of ground loop problem can be solved by using suitable isolation between your AV system and the antenna cable. The simplest way to get rid of the hum is to disconnect the antenna cable from the AV system. If you still want to watch cabe TV or listen to your radio an keep the system hum free then you have to install isolators to all those antenna cable connections your system has __ Designed by Tomi Engdahl
Use a Photoelectric-FET Optocoupler as a Linear Voltage-Controlled Potentiometer - 01/19/12 EDN Design Ideas: The circuit takes advantage of an identical photo-FET as a feedback element. You can use a photoelectric FET as a variable resistor or a potentiometer in combination with a fixed resistor. The H11F3M photoelectric FET has an isolation voltage of 7.5 kV, enabling you to safely control highvoltage circuit parameters. The nonlinear-transfer characteristics of these devices are problematic, however (Figure 1). To correct the nonlinearity, using a simple feedback mechanism as a potentiometer yields a linear response (Figure 2). This circuit uses two photoelectric FETs—one for feedback and the other for applications requiring an isolated potentiometer. You connect the inputs of the two photoelectric FETs in series to ensure the same amount of current for the input LEDs. Design by Sajjad Haidar, University of British Columbia, Vancouver, BC, Canada
Variable HV power supply employs photovoltaic optocoupler - 07/14/14 EDN Design Ideas: This unusual topology saved the day when a higher-voltage variable supply was needed. Design by sajjad Haidar
Widen Opt coupler’ Response - 12/21/95 EDN Design Ideas: Isolation amplifiers provide insulation for low-frequency analog signals at a high cost. Optocouplers cost less and are widely used with digital signals. However, you have to factor in limitations from distortion and bandwidth restrictions when using optocouplers. The bandwidth limits result from a declining current-transfer ratio as a function of frequency. You can use feedback techniques to improve the linearity, but the circuits are usually complex. The circuit in Figure 1, which applies current drive to the optocoupler diode, improves bandwidth and allows easy frequency-response equalization. Design by Ferran Silva, Marcos Quílez, and Ramón Bragós, Universitat Politècnica de Catalunya Barcelona, Spain |
