An optoelectronic device which combines an optical transmitter and receiver in a single package; commonly used in galvanic-isolated control applications such as power supplies.

learn more… | top users | synonyms (1)

3
votes
1answer
39 views

Debugging a PIC16F84A interface with a 4N25 optocoupler

I have a PCB board that I'm trying to repair, the principle of this circuit board is to switch an oven relays one at a time only with a constant rest time, and the switching time is predefined by the ...
0
votes
2answers
36 views

Opto-isolator flow in following circuit

In the OPTO-Isolator used above, I am not getting flow of ckt. According to my understanding, in case of PS8821-2, RD ( of MC ) will connect to SCL( of TPS2384 ) and MC_SCL ( of MC ) will connect ...
0
votes
4answers
69 views

Can an opto-isolated input be analog?

Title says it all: can an opto-isolated input be analog or are they intrinsically digital? Why: I am looking to purchase a relay control board and am deciding between a few options. Here is my ...
0
votes
1answer
43 views

Explain operation of solid-state relay

Link for Datasheet: http://www.ixysic.com/home/pdfs.nsf/www/CPC1230N.pdf/$file/CPC1230N.pdf This is the relay I am using in my circuit, but I am not getting how it connects/disconnects and flow of ...
1
vote
4answers
130 views

Relay alternatives that are silent and support 500mA+

What can I use as a silent "general-purpose" relay alternative? There are various scenarios where I will need a relay-like device that allows me to control one circuit with a separate isolated ...
0
votes
2answers
38 views

Do I need a current limiting resistor for MAX383 digital logic?

I'm trying to control a MAX383 analog switch using a Raspberry Pi, through an optocoupler (Sharp PC817), to separate digital logic from the analog section. On the analog side, I will have a bipolar ...
0
votes
1answer
38 views

LED with opto-isolator does not work

schematic_1 schematic_2 schematic_3 If I wired like schematic_1, L1 and L2 are lighting. But, in schematic_2, L1 is not lighting even though L2 is lighting. When I wired in series as ...
1
vote
3answers
104 views

When do we prefer isolator over optocoupler?

Today I have learned that a device called "isolator" exists (eg: SI8712CC-B-IS). Its function is very similar to the optocoupler's. On the good side, it is much much faster. While it is very hard to ...
2
votes
2answers
95 views

Under what conditions does an optocoupler work fastest?

I want to use the optocoupler FODM452R2 in my design. I want this optocoupler to run as fast as it can (i.e.; work with minimum propagation delay and least rise/fall times). What is the optimum R1, R2 ...
0
votes
2answers
85 views

Is it possible to use capacitor for isolation instead of optocoupler?

I designed a Buck converter which drives several LEDs. The PWM signal, which has a certain fixed duty cycle, is generated by a 555 timer IC. The circuit which drives the Buck MOSFET, including the ...
0
votes
1answer
52 views

Water pump with opto-isolator MOC3063M and triac BT137

I have designed a circuit for water pump. Please correct me if I am wrong with schematics. The idea is to to switch on/off AC motor pump with 230V and 7.5A, when water is detected. I have used ...
0
votes
1answer
97 views

Normally closed SSR won't work with grounding out a magneto's primary to ground

I've been trying to find a device that will ground out a magneto's coil (primary kill wire) in a normally closed state without using a mechanical relay because I want my circuit to be all solid state. ...
0
votes
1answer
77 views

Arduino controlling high voltage DC source, Opto-Isolator

I need to create a circuit that I can use an Arduino to control a 400~500 DC voltage source. I am not used to opto-isolators, but I was thinking about using it to separate both systems. But I cant ...
0
votes
0answers
21 views

How can I control an IR204E in a PK543A to remotely operate this apartment door buzzer? (What relay do I need?)

My apartment door 'suite station' (buzzer) is a TekTone IR204E (pdf). It has an option for talk, listen, and open door. It contains four wires labeled 1, 2, 3, and X. My research leads me to believe ...
0
votes
1answer
45 views

How does this motor drive circuit work?

The Drive terminals are connected to a PWM signal generated by an arduino micro controller. The purpose of this circuit is to isolate the arduino from the motors to avoid too much current being drawn. ...
1
vote
1answer
19 views

Cell Voltage Relaying in a Battery Management System

Question: If I have 48 lithium cells connected in series as a pack, how would I best go about physically implementing a system to measure, isolate, and relay cell voltages to a centrally managed ...
0
votes
0answers
52 views

Dimming SSR Circuit - Verification

I am designing an SSR circuit for the purpose of controlling Christmas lights. Specifically I have the following two goals. Switching & Dimming incandescent strings Switching LED strings - I ...
0
votes
3answers
94 views

Very wide range high voltage measurement with optical isolation

I have a voltage source I'd like to measure, it is from 0V to 1kV, any value in that range. The accuracy isn't that important, but measuring with an accuracy with 1-5% would be perfect. This has to be ...
1
vote
2answers
59 views

Can I create a totem-pole structure by using two optocouplers?

I have two optocouplers. One of them uses NPN transistor and the other one uses PNP. Each of them explicitly give the base pin of their BJTs out. Can I make a totem pole structure by connecting them ...
1
vote
2answers
110 views

Need an optocoupler for getting directly proportional output galvanically isolated from the DC input

I want to use an optocoupler to linearly step down a DC voltage which willy vary from 0V to 400V. That is, I want the output to be directly proportional to the input and I want it to be galvanically ...
1
vote
2answers
148 views

Detecting Zero Crossing of Mains (Sine and Square Wave)

I need to design a circuit that can measure and output pulses for a MCU at zero crossing of 220VAC waveforms. The application requires that that both square wave waveforms and sine-waves should work. ...
1
vote
3answers
134 views

Operation of PC817

I am studying a DC-DC converter circuit design which has PC817 photocoupler in it. I am confused with the way PC817 behaves. My friend says that it is an analog photocoupler. I have tested it myself ...
4
votes
2answers
242 views

Opto-coupled RS-232 receive circuit

I am looking into a implementing a low-cost RS-232/422 opto-coupled receive circuit. The aim is surge protection and tolerance to DC offsets. The challenge is that the inputs should be completely ...
0
votes
1answer
66 views

How to use LM56 to switch on/off a 2kW heater

I have an oil heater at 220V/2000W so lets say 10A. I was thinking of creating a circuit to switch the oil heater on/off with a LM56 (http://www.ti.com/product/lm56). Is it possible using a relay or ...
0
votes
2answers
93 views

Optoisolation and Mosfet combo

I want to switch a Thermoelectric Peltier Cooler (TEC1-12705) (12V - 77 Watts) using an Uno. I am an engineer but not an EE so I could use some guidance on circuit setup. There was a very good ...
1
vote
1answer
76 views

Using PS2501A-1-A Optocoupler. Need help understanding datasheet

I'm experimenting with circuits to trigger my camera shutter and camera flash. My plan is to build a 2-stage trigger for high speed photography that triggers the camera a fraction of a second before ...
1
vote
3answers
90 views

Safe microcontroller input from 8.4V circuit

I have an airsoft rifle which uses an 8.4V battery to drive a motor when the trigger is pulled. The circuit is that simple, just a battery, motor and switch - there's also a 15A fuse. I want my ...
0
votes
1answer
188 views

Two circuits with different voltages - should I use a transistor or an optocoupler as a switch

I am doing a project using the output of a Raspberry Pi GPIO pin (3.3V) to power a 12V remote control. If the two are on different circuits, can I use a transistor to switch on the 12V circuit or do ...
0
votes
0answers
69 views

Optocoupler for AC to DC current sensor

I am designing an AC to DC current converter. The specifications are as follows: input: 0 to 5A output: 4 to 20mA supply: 230VAC Now I want to isolate the input and output. What would be a ...
2
votes
2answers
601 views

Creating an opto isolator board for Raspberry Pi

I have a relay board which I bought from dx.com and I am not sure about its reliability. If it fails, then it may harm my Pi right? So I googled around and read that opto isolator provide complete ...
2
votes
2answers
182 views

Simple light bulb operated by button and optoisolator triac

I'm new to the world of electronics and I have a quite simple question. Can I control my light bulb with something like this schema? Power source is regular AC 230V (~320Vrms) source. Here is ...
0
votes
2answers
65 views

opto voltage specification question

The datasheet is here http://www.ssousa.com/pdf/SLC800.pdf . I need help on the following: Where is the maximum operating DC voltage is specified? It appears to be 500VDC but I am not sure. I ...
2
votes
2answers
254 views

Optocoupler design

I need to design a MOSFET control circuit which is driven from an FPGA through an optocoupler. Following are the conditions required to be met in my design: When the power is up initially and the ...
2
votes
2answers
52 views

Flipping Output Logic

I have the following circuit: The diagram above has a pot between VCC, LM393 and Ground, on my board pictured below this is replaced by a voltage divider with two 10k pots. It looks like this: ...
1
vote
1answer
281 views

Isolating PWM From H-Bridge

I have a H-bridge based on FAN7392 drivers. This bridge works at 350VDC to output a approximately 240V 50Hz waveform. This circuit is isolated from rest of the board and I would like to maintain the ...
3
votes
2answers
470 views

How to combine PC's power and HDD LEDs?

I'm going to buy a PC tower case which has only one LED intended to be used as the power LED, thus no HDD LED is available. My intention is to have that single LED at about 50% of its intensity when ...
0
votes
2answers
239 views

Why I can't get a clean signal from my opto-isolator?

I am trying to get working my first Mosfet H bridge. My H bridge characteristics are: 12v power supply 3.5A max current I need to control the bridge from a microcontroller 5V output About 30KHz PWM ...
1
vote
3answers
653 views

How do I drive a MOSFET working under high voltage while keeping it insulated from the rest of the circuit?

I want to drive a MOSFET with a 50Hz, 50% duty cycle clock pulse. The voltage to be switched is as high as 300V DC. The section inside the dashed lines will stay electrically isolated from the rest ...
0
votes
3answers
297 views

How to drive optocoupler with BJT properly [schematics]

Recently I asked a question about optocoupler: Shematics: optocoupler controls a transistor and doesn't work as expected I have one more question related to the topic. PWM input comes from the ...
0
votes
4answers
257 views

Shematics: optocoupler controls a transistor and doesn't work as expected

I'm applying optocoupler TLP521 to decouple microcontroller Atmega88 (on the left of the schematics) from the power circuit. I have a problem understanding why the schematics below doesn't work in ...
0
votes
2answers
210 views

Debugging a garage door opener circuit with an optocoupler and mosfet

There seem to be many related questions, but I can't quite find the answer I'm looking for. I've got a garage door opener switch. There's 16V across the wires, and when you short them, the garage ...
4
votes
2answers
116 views

How are the values for the resistances and capacitor chosen in the circuit below

In the circuit shown, the optocopuler is used as a solid state relay and the triac acts as a switch. i would like to know how the resistor values and capacitor value was chosen.
0
votes
1answer
160 views

What are important design parameters for Opto-isolators? [closed]

I want to use an opto-isolator in my circuit. I found Opto-isolator 6N135 matching with my design voltage requirement. datasheet (http://www.vishay.com/docs/83604/6n135.pdf). But datasheet seems to be ...
1
vote
1answer
100 views

What is this Circuit's function? Does it involve Isolation?

My question is: Does this circuit isolate the "X Volts" lines from ground (1) If not, how should I implement an opto-coupler to provide isolation between the data lines ("X Volts") and ground? ...
3
votes
1answer
246 views

LED and photodiode characteristics at very low currents

I'm trying to understand the coupled characteristic of a classic 4n35 optocoupler, used in reverse biased photodiode mode (I'm only using the B-C junction only). Over 1mA input forward voltage, the ...
0
votes
2answers
2k views

How to connect a Inductive Proximity Sensor Switch NPN DC6-36V to PIC18F4550 5V

I have got a LJ12A3-4-Z/BX Inductive Proximity Sensor Switch NPN DC6-36V with this Specifications: Model: LJ12A3-4-Z/BX Theory: Inductive Type Sensor Wire Type: Cylindrical DC 3 Wire Type ...
0
votes
2answers
578 views

How can I use optocouplers with function generators?

I am using optocoupler PC817 to create optical isolation between my digital signal and arduino due and arduino mega 2560 . And I am using external pull-up resistor connected with 3.3 V (to pull up ...
0
votes
3answers
157 views

High frequency mains sensing

I want to sense mains voltage at a frequency faster than 5000Hz, with a microcontroller. The idea behind this is to visualize the actual shape of the AC voltage, and eventually to compare it with the ...
0
votes
3answers
119 views

Light controlled h-bridge?

I was wondering if it would be smart to control a power H-bridge, with light. Imagine an opto-isolated power stage, where the opto-isolators are sawed in 2 parts connected by an optic fiber. I think ...
2
votes
3answers
319 views

Optocoupler Issue - Not sure why it isn't working - help needed [closed]

I have used an optocoupler/isolator before in a similar circuit, can't figure out why it isn't working in this instance, any help would be much appreciated. I am using the Siemens SFH615A, link to ...