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.
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6answers
408 views
Optoisolate two ICs sharing same power supply
I have two ICs. The former acts like an ADC, measuring the voltage in a power outlet and transmitting the result to the last. Both ICs requires 5 Volts to work.
I ...
5
votes
4answers
4k views
Digital Dimmer With Microcontroller
I want to build a digital dimmer for resistive Loads.
I have found this circuit for that:
The input voltage is 220VAC 50Hz.
The red box in the picture is for ...
2
votes
1answer
338 views
how to interface HCPL-3700 optocoupler to an input pin of ATmega16L
I want to detect logic of the mains supply (230VAC, 50Hz) and feed the output of HCPL-3700 into ATmega16L. I read through the datasheet but could not understand how to calculate the resistor values. ...
9
votes
2answers
2k views
How do I select the accompanying components for an optocoupler?
I'm using an optocoupler (MOC3021) to sense the On/Off state of an electrial appliance using a microcontroller ATmega16L. How do i go about doing this? My mains supply specs are 230V, 50Hz. How do I ...
1
vote
1answer
287 views
How to determine whether electrial appliance is On or Off using ADC or Optocoupler
I want to sense the On/Off state of an electrical appliance (e.g. light bulb 100W) using a microcontroller ATmega16L. How do i go about doing this? My mains supply specs are 230V, 50Hz
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vote
2answers
516 views
Safely driving a high power h bridge with optocouplers
I was looking into some high power H bridges (I was hoping to make an induction heater or at least a high voltage power supply). Some I came across are: this, this and this, to name a few.
I noticed ...
1
vote
3answers
436 views
detection of absence of 118V DC voltage using optocoupler
I want to use an phototransistor interfaced with microcontroller to detect absence of 118 dc voltage.The problem is how to calculate the right resistor value of the input(LED) circuit as well as ...
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votes
3answers
358 views
Photo-couple/opto-isolator that stops current through the output when current flows through the input?
I was looking into designing circuits around photo-couples/opto-isolators instead of transistors, but I have found that I need an inverter of sorts. I need something that stops current flow through ...
3
votes
1answer
446 views
Zero Cross Detection Circuit for line voltage [duplicate]
Possible Duplicate:
How can I detect a power outage with a microcontroller?
I'm doing some research with the goal of eventually creating a light dimmer controllable from a micro controller. ...
2
votes
3answers
924 views
Measuring voltage/current digitally on two separate power supply rails
I'm designing a dual-rail DC power supply, with the two rails completely separate (except for sharing a dual-secondary transformer). The main design should work as-is, only by adding a fuse + mains ...
1
vote
2answers
240 views
USB separation in RF design
I'm designing an homebrew RF spectrum analyzer.
Controlling the analyzer will be done using USB which is converted to UART using an FTDI chip.
My concern is that noise (probably common-mode) will be ...
1
vote
2answers
219 views
Connect a microcontroller to a gadget
Although I have average programming skills, I'm not far from being an noob concerning electronics!
I therefore want to kindly ask you to help me connect my (already programmed) Arduino Uno to the ...
5
votes
3answers
3k views
When should I fire the TRIAC's gate when controlling an inductive load (AC motor)?
I'm using a combination of opto-triac + TRIAC to control a 230V AC motor with a microcontroller. For detecting the zero-crossing of the voltage I'm using another optocoupler.
I know that the AC ...
4
votes
4answers
401 views
Why are optoisolators white?
I've noticed that most of the opto-isolators (optocouplers, opto-triacs) have a white package. Why is that?
0
votes
2answers
558 views
What does 'random phase' means in a triac driver?
I'm using this triac driver to control a triac. In its datasheet it says 'provide random phase control of high current triacs [...]'. What does that mean? It doesn't have zero-crossing detection?
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vote
1answer
502 views
Is this galvanic isolation?
I'm doing a project which consists of 2 big parts: a control part (a microcontroller with I/O pins expanded, USART-to-USB, a RTC, an EEPROM, a LCD) working @ 5V and an actuators part (optocouplers for ...
3
votes
2answers
726 views
Is a protection diode needed on a TRIAC optocoupler and what for?
Please refer to page nine of the Sharp S108T01 / S108T02 datasheet:
Is this diode needed - why/why not?
How do I choose the correct diode, if yes?
UPDATE: Thank you all for your educational ...
3
votes
2answers
895 views
Difference between Zero-Crossing Optoisolator and Regular Optoisolator
I am trying to find any documentation on what the purpose is of a Zero-Crossing Circuit TRIAC Optoisolator. The datasheets don't explain the concept well enough. If you do answer, please include ...
1
vote
1answer
2k views
Choosing components for a triac's snubber
I'm interfacing the BT139-600 TRIAC with this MOC3051-M Opto-triac. I want to build a snubber circuit for the TRIAC as shown in the MOC3051M opto-triac's datasheet @ page 8, figure 12.
The load ...
8
votes
3answers
10k views
How to drive a MOSFET with an optocoupler?
What's the proper schematic for driving this MOSFET from a microcontroller pin through this or this optocoupler?
The MOSFET will drive a motor @ 24V, 6A.
4
votes
4answers
948 views
Sanity-check on snubber design
I keep frying resistors in the following optocoupler and triac snubber circuit, and I'm not sure whether to attribute this to bad design, or to faulty components.
There are no observable sparks at ...
8
votes
2answers
960 views
Why Snub an Optoisolator?
I am using an optocoupler and a power triac to switch 120VAC supply to an ~108 watt fan. The datasheet for my optocoupler requires me to snub the optocoupler output when I'm switching an inductive ...
1
vote
1answer
2k views
How to use a phototriac coupler to trigger the main triac?
I have in my box of parts a phototriac coupler, namely a Sharp PC3SD21NTZ (datasheet), which is a zero cross type. I don't know how to use it, but I've been meaning to learn for a while.
This part is ...
2
votes
1answer
627 views
How to properly Bias a Opto Coupler
I had some problems setting up a Opto Coupler today. The data sheet is here. I set it up putting a 470 ohm resistor to ground from the cathode (pin 2). I am understand the selection of this resistor ...
3
votes
4answers
2k views
120VAC 60Hz Zero Cross Detector
I'm designing a digital phase-controlled light dimmer, and I need a zero-crossing detector circuit. From what I've read, it's a bad idea to wire the AC main directly to the microcontroller through a ...
4
votes
5answers
2k views
Opto-Isolator For Volume Control?
I'm doing an Arduino based project using the PWM hooked up to a 0.5W 8Ω speaker in order to make various sounds, I want to implement a digital volume control and I thought about using another PWM ...
