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159 Threads found on edaboard.com: Optocoupler Circuit
Hi, I assume there are ready to buy DC/DC converters with medical approval. Generally you need extended gap and creepage distance. Reduced leakage current, reduced capacitive coupling. You could build it on your own by usung a small (but according regulations) small pulse or signal transformer. (optocoupler needs to be carefully chosen, too. And
Dear Friends , I have a solenoid valve rated 6W , 220 v AC. That is when switched on via a relay then it gets the supply and it draws around 58mA as checked by clamp meter . Now I want to check whether the solenoid vale is turned on or not using a microcontroller pin and optocoupler 4n35. I have used a circuit also but it seem
thats a switching mode power supply circuit and I guess its a fly-back type (I see pc817 optocoupler). the transformer is ferrite core switching transformer with two output winding the transformer is specially designed for that circuit you can find design information in switcher IC datasheet or application notes
You need several 1000 V withstanding voltage and respective creepage and clearance distance for safe mains isolation. The part is absolutely unsuitable. - - - Updated - - - Consider a primary voltage measurement circuit and an optocoupler transmitting a digital "voltage good" signal.
Hi, The use of an optocoupler is useless when both sides are referenced to the same GND. It's a waste of money and a waste of current. A microcontroller usually has an ADC....if you use just two resistors as voltage divider and a capacitor then * it saves money * it saves current consumption * it saves board space * it is most flexible Klaus
What would you recommend then, using longer switching times? 1 period on 50Hz is 20ms long, for example: For 25% power optocoupler input high for 100ms, low for 300ms (5 periods on) For 50% power optocoupler input high for 200ms, low for 200ms (10 periods on) For 75% power optocoupler input high for 300ms, low for 100ms (15 (...)
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 ?
Hai, I am designing a BLDC motor driver by using TLP250 using STM32f402 micro-controller. Now i have been stuck with optocoupler output,after reading hall sensor output i have triggered one high level mosfet and one low level mosfet. But when i read gate voltage there is no such gate trigg
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 (...)
Hi, I'm trying to send data from one arduino to another arduino via optocoupler. my sending speed is 9600bit/sec. i'm using 4n35 optocoupler, one arduino mega and one arduino uno. Can anyone help me ?
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
This is a very simple dimmer with a triac output (phase control). It uses timer0 to do the timing. The code is written in mikroPascal. The control part (here a P12F629) is competely isolated from the 230V mains supply: - the zero crossing detector contains an optocoupler (4N25 or similar), - the drive of the triac also conta
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.
Is there any optocoupler ,which can be used for isolating analog signal?
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 fear, the problem isn't clearly specified. What do you exactly mean with "protect the microcontroller"? In many designs, isolation between control circuit (e.g. microcprocessor) and DC bus is required. Of course, isolation involves protection against damage by a defective power stage, but that's not it's primary purpose. If the control cir
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.
Usually PWM ic S3525 circuit is connected with battery so it needs isolation. This isolation is provided by the transformer. On the secondary side is 311V DC and 220V AC generator circuit which has mcu, does not require isolation. If you require isolation there too, hi speed optocouplers are required. A pulse driver transformer can also be (...)
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
You could, I expect, use the optocoupler as an emitter follower and avoid saturation. Provided that the pin receiving the follower output is happy with a somewhat reduced output voltage. If you trigger on the turning-on edge, and your frequency & min-off-time of the coupler is low enough to let saturation recovery tun its course, then fine. Trig
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 (...)
If the output waveform shown above is the output of an optocoupler then you need to change the optocoupler only... For faster response, you should use high speed optocoupler like 6N137 & this is not a transistor. Its a photo transistor & there is a lot of different between these two. Try to ask questions with full details (Clear (...)
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?