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153 Threads found on Optocoupler Circuit
hello dear forum, in the datasheet of TLP250 it says "not recommended for new design " what can I use instead for my project ? 2) can I make a simple diode - cap bootstrap circuit to eliminate the need for another isolated supply for high side drive with this optocoupler ?
I presume the TLP cathodes are directly connecting to STM32 IO pins? STM32 GPIOs can basically source or sink the required TLP drive current. But the circuit is completely wrong. - individual series resistors for each optocoupler required, power supply must be 3.3V - high side drivers can't use common power supply, need either three DC/DC con
I need to design a optocoupler circuit as shown in the attached datasheet of IL300 optocoupler IC. I designed the circuit as shown in the first page of pdf. I used OPAMP OP-07. I did'nt used the output OPAMP in the circuit. I applied a sine wave of few hundred hertz at the input. It gets reflected at the (...)
Hello, I'm trying to design light dimmer for driving the LED bulbs. Initially design was based on standard triac circuit with optocoupler. Unfortunately that solution wasn't especially good for driving low power LED bulbs at small PWM values. I have searched internet and I found how to make alternative circuit with galvanic isolation (...)
When I put in more than 1 opamp the power pins are connected and in most cases that is fine. In my current circuit I am implementing a linear optocoupler (HCNR200) to isolate HV from LV circuits and I want the opamps on different supplies. I cant find a way to disconnect the power pins. It is not critical as I am able to disregard the (...)
is that possible to transmit the data from one arduino to another arduino through optocoupler using rx and rd communication and display it at lcd? You did not select TX pin from ARD1. I'm not sure if Arduino environment was conceived to support selecting any other pinout for that function, but those pins labeled on th
I have an optocoupler board as shown in figure . Though the circuit is working fine in simulation. I actual hardware theres is some wiring error which unable to debug. I am finding that the output is having pulses of peak 7.5V instead of 15V. When no pulses are given to the board, the ouput is 7.5V. What could be the reason. Thanking you. [url=
Thanks FvM and betwixt for the reply. I would like to know if there is any way to control the dead time using the given circuit as its already on a PCB. Specilfically what resistances have effect on the dead band. I am also attaching my controller outputs. and output of optocoupler
The Topswitch-jx range of flyback controllers are the best in the world. Why do they not boast about their unique superb output short circuit protection feature? In a topswitch-jx, the actual operating current to supply the topswitch actually comes from the feedback optocoupler. This unique feature means that if the output gets short (...)
You are correct about your concern, the LED in the optocouplers does degrade over time I would review my previous assumption, and now agree much more with your assertion. In fact, for some reason ( perhaps, intrinsically due to the GaAs substrate itself ), the failure rate of the optocouplers are much large
Hello guys i managed to make a firing circuit see the image attached. the result waveforms are also attached, color green is the trigerring pulse. My question is why i get the timestep too small when i insert the moc3041 which is the optocoupler used to propagate the signal to the gate of the scr. Any ideas about this one. ( circuit (...)
If you want faster edges than 400 ns, you must not drive the PMOS transistor gate from a optocoupler with open collector output. Instead use either a fast BJT circuit or better a fast CMOS logic gate. - - - Updated - - - You didn't tell what the final output load is, but the main problem is the large PMOS ca
the zero crossing detector contains an optocoupler (4N25 or similar), The opto 4N25 has not a good gain, so that for low angles the circuit will not be able to detect precisely the phase where zero cross happens.
Sensing mains voltage can be of course done with an optocoupler and is often done this way. Use sensitive optocouplers to reduce the series resistor power dissipation to an acceptable amount.
As I said I am not getting expected results as in the figure. So you want us to guess about your unexpected results instead of telling your observations? A few guesses are free, however. I expect circuit #1 to self-trigger without optocoupler input due to dV/dt or leakage current. There should be base-emitter resistors (e.g. 1
thank you for your reply....can u please provide me a link for refernce design?? simply this circuit will help you. You will take zero cross detection point and fire the optocoupler depends on duty cycle.
How (in which circuit) are you using 4N35 as a gate driver, it isn't but a basic optocoupler?
optocoupler is not at all necessary. The standard way to do this is to set the AVR to pull up the pins connected to the micro-switches, and have the micro-switches complete the circuit to ground when closed (assuming they are normally open). It might be worth adding a capacitor (perhaps 10uF) between the AVR pins and ground to denounce them.
Has it already been mentioned that the IGBT driver must provide isolation between the control voltage and the gate circuit? It's a very slow control signal related to usual IGBT application, so anything e.g. a slow optocoupler could be used to isolate the control signal. But you also need an isolated power supply for the gate driver. Can be a sm
Greetings, Does this circuit work well? Application : to control speed of ceiling Fan or to control brightness of a Light bulb. Components : MOC3021 (optocoupler), BTA12 600 (TRIAC) 110117 Thank you !
Hello All, I am trying to drive triac with Positive Power supply. With positive power supply it should be possible to drive triac in Q1 and Q4. Here is the circuit I am using. But triac is not triggering. I have checked in oscilloscope the signal on gate looks good enough. 110099 I really need your expert
optocoupler solution from EDN:
Hello, I have a circuit and I am trying to find its problem. I have square pulses at the tlp250 input (pin3, 5 V peak-to-peak) but I have no output at all (pins 6 and 7 of TLP250). There are six TLP250 to drive the BSM10GN60 IGBT module. Three of them has their Vcc connected together but the other three Vcc are not connected together and are sep
Hi, here is no mention of it in the datasheet. Look at the section "Absolute maximum rating". I bet it is mentioned. To the circuit. It would be helpful to show us... Is the second line of the AC connected to your expander device gnd? You are aware of the risk of electrical shock? I reccomend to use an optocoupler to get galvani
It does seem like there would be no use for a optocoupler with a common ground. Sometimes they are used when someone wants "isolation" not realizing that such a connection does not achieve the desired result. Can you post the circuit?
Short answer: no. 5V (less the LED drop) across 100K would only give you about 30 microamps. Unless you have an optocoupler that can work with this low current, you'll need to find another method. I'm not sure what you mean by "My scope is need to check the voltages". If you are using a scope, what do you need optos and rectifiers for?
I think the optocoupler cannot source the current required by the lamp. what type of lamp you are per the optocoupler datasheet, only it can source 10mA current. Try replacing the lamp with a LED to verify your current demand.
I have designed a dc dc converter i.e from 12vdc to 311vdc.which is regulated. I have used sg3525 . The feedback is eshtablished using voltage divider resistive network at 311v side . I want to use 4n35 optocoupler instead of directly using voltage divider network so as to isolate low voltage components from high voltage.i havn't used 4n35 ever .
The only thing a zener and an optocoupler have in common is that they both have "er" in them. Why do you have a zener in your circuit? Why do you have that other diode? Why do you have two 10Ks in series with that zener that you don't need? What is it you actually are trying to accomplish?
hello, will this ckt work?? R1=R2=22k 2 watt.. whether it will blow the optocoupler ?? please help... . Reverse diode is usually not included into the photocoupler and must be added.. this could be work ... without transform this output as DC average... I suppose you will send the square 50Hz signal in
I am using a microcontroller to drive hbridge . Is there any optocoupler which i can use between microcontroller and ir2110 to protect the microcontroller ?
Last year for Christmas I did chaser circuit with AT89C4051+bc547+BT136, it was not recommended by this forum, (I was warned against bringing MC in contact with mains supply) was told to use an optocoupler. It just worked and was not perfect. And now - For using opto, as a prelim, I used PC817 separately , I connected it to 5v supply using 560
Are you aware of the huge signal delays caused by the optocouplers? Depending on the intended switching frequency, fast logic optocouplers might be required.
Dear Members, I am designing 2 KVa pure sine wave inverter system , using SG3525 to step up 24 Dc to 320 Dc , and then using IR2110 to make pure sine wave by SPWM signals from pic16f684 . I have a question that should I Use any optocoupler (like tlp250) between Microcontroller and Driving circuit or should I give signal directly to IR2110. (plz su
hi all. im trying to simulate this voltage sensing circuit for the output voltage of a boost converter. its an LM358 + an IL300 linear speaking the circuit seems to work fine in all the range of my output voltage the only issue i have is that for a voltage >~ 280V
I am using pulse train to trigger TRIAC and using moc3021 optocoupler to trigger triac ...circuit is working with frequencies up to 30Hz but i want to work with 50Hz/230V but it is not working....please chek circuit...and help me...please friends.. waiting for your replies 8-) 96659
In page 9 (bottom right hand side) of the following, it talks about not saturating the optocoupler transistor in the cascaded opto feedback network. Why should it matter if the opto transistor saturates?
Hi there, I am successfully using the attached ECG circuit to get ECG signal. The problem is that this circuit needs two separate 9V DC batteries - one for the amplifier circuit & other for the isolation circuit (which has an optocoupler). This safety feature is great when one is physically (...)
what do u mean by fetch data...... use optocoupler with 220k resistor for each phase having star configuration
The circuit doesn't seem to make sense. Why you are using an optocoupler? Obviously there's no isolation problem. The circuit however suggests that the problem is about an unmodulated IR "beam". It will in fact suffer from ambient light, direct sunlight is the worst case. Optics is most likely required to make it work. Most optical (...)
The input is a high voltage pulse signal, I would like convert it into TTL signal so the microcontroller can capture the pulse width. I use optocoupler to isolated the the high voltage signal.
the dimmer circuit I'm using uses a potentiometer so I just need something to operate the potentiometer from a distant Whether u r ready to replace POT with optocoupler? or u wanted to operate the POT with a motor setup? How many steps brightness control u want? RF or IR/LASER? (RF is better) micro controller based or without u
hi all i want to know how make a solid relay state i tried to use mosfet irf730 to control as switch 12 vdc max 10 amp . drive microcontroller and optocoupler but mosfet heated i want help to make a solid rely and the circuit. thanks . Hi fawzy73 To design a solid state relay you need to use combination of one P mos and one N mos
thanks. someone protecting port with optocoupler. why we must isolation with optocoupler?
@pplus can u tell what u mean by Vka? is the cathode voltage of tl431 or that of the optocoupler? thanks
Do you want to test the optocoupler or the FET? And is this an in-circuit detection, or do you want to check components on the bench?
Hello, This is a really big problem in using triac for switching AC devices using microcontroller and optocoupler.I made a circuit which uses optocoupler MOC3041 and triac BTA16-600BWG.Due to the minor delay in switching of Triac there is a jitter at the zero crossing of the signal.This has resulted in burning of coil in my lower quality (...)
Actually there is '-' ,'+', and comp terminals for sg3524 pwm controller.. i m designing isolated converter for our application. i need to isolate the voltage sensing which is given to '-' terminal of the error amplifier.. how to acheive it..? any idea or example circuit..? Usually i used to go with tl431 and optocoupler at the feedback side to
is it possible to give 230v ac input directly to any optocoupler
Hi scmojks As i can see , the circuit has a big problem ! when optocoupler is on , the transistor can be destructed because you don't have any resistor in BE diode , path . Best Wishes Goldsmith