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Battery powered Amplifier has optical isolation - 6-Jun-96 EDN Design Ideas: When you interconnect scientific instruments, especially older ones, you often need both gain and galvanic isolation for the analog interface functions Design by W Stephen Woodward, Venable Hall, University of North Carolina, Chapel Hill, NC
Circuit Compensates Optocoupler Temperature Coefficient - 11/22/01 EDN Design Ideas: When using an optocoupler in a linear application, you should consider its gain drift with temperature. Traditional single- and dual-transistor-output devices have a notable gain drift with temperature. In recent years, some temperature-compensated optocouplers have appeared. However, another option is to use two optocouplers or a dual optocoupler with appropriate feedback to make the dri Design by J Michael Zias, Acme Electric Corp, Cuba, NY
Circuit Protects Computer's Input - 05/26/94 EDN Design Ideas: The circuit in Fig 1 performs input protection, level translation, isolation, and debouncing. The circuit allowed the output of a relay driver to connect to a computer even though the relay driver delivered a voltage as high as 24V and the relay driver had no ground connection. With the values in Fig 1 the low and high thresholds at the circuit's Design by Ang Tzu Seng, Halliburton Drilling Systems, Singapore
Circuit Provides Universal Ac-Input-Voltage Adapter - 08/25/11 EDN Design Ideas: Use a TRIAC and optocoupler to automatically change between doubler and bridge configurations. he input-rectifier stage of an offline power supply converts an ac-line voltage to a dc voltage, which powers a dc/dc converter. If you configure the rectifier section as a full-wave bridge for a universal mains input of 92 to 276V rms and 47 to 63 Hz, you must design the dc/dc converter to operate over a wide range of input voltages. This approach increases the cost of components and reduces the efficiency of the dc/dc converter. Design by JB Castro-Miguens, Cesinel, Madrid, Spain, and C Castro-Miguens, University of Vigo, Vigo, Spain
Circuit rejects Ambient light - 06/10/99 EDN Design Ideas: In some applications, you need to detect light signals in the presence of background light whose intensity can change by orders of magnitude. The circuit in Figure 1 uses an integrated photodiode/amplifier (OPT201) in conjunction with an integrator that drives two linear optocouplers (TIL300). Design by Massimo Gottardi, IRST, Trento, Italy
Circuit Widens Optocoupler’s 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
Compensate for Optocoupler Temperature Coefficient - 11/22/01 EDN Design Ideas: When using an optocoupler in a linear application, you should consider its gain drift with temperature. Traditional single- and dual-transistor-output devices have a notable gain drift with temperature. In recent years, some temper Design by J Michael Zias, Acme Electric Corp, Cuba, NY
Cross-coupled gates prevent push-pull-driver overlap - 05/15/08 EDN Design Ideas: Cross-coupled gates in the push-pull drive of a center-tapped transformer's primary prevent overlap Design by Richard Rice, Oconomowoc, WI
Drive High-Voltage Varactor Diodes From just 5V - 03/27/97 EDN Design Ideas: How to connect two International Rectifier (El Segundo, CA]PVI1050s photovoltaic-isolator ICs in series to provide a20-Volt tuning drive for the varactor diode. Design by Steve Hageman, Hewlett-Packard Co, Santa Rosa, CA
Dual Amp for Use with Opto Compressor Project - PCB. ZIP containing schematic and gerber files. __
Dual JFET-992/993 PCB - containing schematic and gerber files. For Use with Opto Compressor Project __ Contact: info @ forsselltech . com
Fast analog isolation with linear optocouplers - EDN Design Ideas: 06/12/2014 Implement isolated analog signals and current loops with linear optocouplers Design by Avago Tech Note
Generate 0.5v Negative Supply - A while back someone needed a simple way to generate a negative 0.5v supply from a conventional transformer type AC to DC power supply. The circuit below uses a couple schottky diodes and a filter capacitor to perform the feat . . . Hobby Circuit designed by David Johnson P.E.-July, 2011
Improved Optocouplers Reduce Current Draw, Resist LED Aging - 14-Dec-07 EDN Design Ideas: With improved optocoupler circuits, you can enhance the accuracy of zero-voltage sensing Design by Peter Demchenko, Vilnius, Lithuania
Light powers isolation Amplifier - 01/21/99 EDN Design Ideas: Self-powered isolation amplifiers, which need no external isolated power supply, provide versatile and convenient interfaces in many applications that require galvanic isolation of the signal source. Examples of such applications include circuits that serve in industrial or medical environments, in which isolation Page includes
several designs. Scroll to find this one Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC
Measure 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
NEC Single & Multi-Channel Optocouplers 3/20/03 - App Note Doc #956__ California Eastern Laboratories
Negative 0.5 Volt Supply - This simple circuit consists of two LEDs and a photo diode. It generates a negative voltage with a current level of a couple milliamps. It is ideal for supplying a negative rail to low power “rail to rail” op amp circuits, which need to have a true zero volts output. Note: This circuit is not particularly efficient . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006
Novel isolates temperature sensor from its host - 08/03/06 EDN Design Ideas: Temperature-to-period converter and transformer driver provide power and signal isolation Design by Alfredo H Saab and Tamer Mogannam, Maxim Integrated Products Inc, Sunnyvale, CA |
