A TRIAC is an component often used to control high power currents, both as a switch and as a "dimmer"-like construction for controlling lamps or electric engines.

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Dimmer Tutorial Using Diac and Triac [closed]

I want to make a dimmer circuit here in our house as Christmas gift to my self. But I am still student with limited knowledge so please kindly guide me and help me to build this my self-assessment ...
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74 views

Filtering out TRIAC's triggering current spike on the mains

I've got my 2KW heater controlled by a home-made dimmer, on 230V/50Hz mains. It's using the common TRIAC delayed command process. The TRIAC (BTA24-800BW) is a snubber-less kind, drived by an (non zero ...
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97 views

Do I need zero-crossing detection for controlling a heater?

I need to control a heater element (about 500W) using arduino. For switching part I would go with zero-crossing SSR or zero-crossing optoisolator and triac (the second seems to be cheaper). The ...
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89 views

YTR816-600E datasheet, in English preferably

I bought a cheap Chinese dimmer which uses only this three-pin and heatsinked YTR816 power semiconductor [almost certainly a triac] and a DB3 diac. The rest of the components are passives: tree 1/4 ...
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68 views

Driver for triac

Can you explain this schematic: Especially part where are optotriac and triac. I can't understand why if turn on optotriac \ then main triac will be open. Because I made a real scheme and ...
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1answer
78 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 ...
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68 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 ...
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3answers
100 views

Triac power switching

Given the circuit below: (I simply plan to switch the light bulb on/off and I will later add an optotriac to the gate.) As I understand, the circuit should work in this configuration, and the ...
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2answers
173 views

TRIAC turning on asymetrically by itself when it gets warm

I've got a simple triac phase angle controller which is very similar to the MOC3021 data sheet app circuit. Most of the time everything is fine. The circuit looks like this: The triac is a ...
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5answers
214 views

How to throttle power consumption of a heating coil?

Which is an appropriate but simple electrical circuit to reduce the energy (power) consumed by a heating coil which has an AC feeding without generating an asymmetric load (large DC component, e.g. ...
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2answers
123 views

How to replace the rectangle(DIP) bridge rectifier with round one.

I want to make an AC dimmer and the circuit diagram from the instructables uses a bridge rectifier which is in DIP package and rectangle in shape and the rectifier which I have is round one, so how ...
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1answer
45 views

triac DC ground and AC live

In this example of using a 3Q triac, could the AC voltage flow into the DC terminal?
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3answers
121 views

How fast should a Triac be switched for a dimming application?

I want to create a dimmer using a Triac - it will have a duty cycle where it is on for x% of the time, and then off for Y% of the time - my question is how often should this on/off cycle happen? I ...
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2answers
324 views

Snubber causing more problems than benefits

When designing and building a simple motor controller i used 2 snubber circuits, one to protect the main triac and another one the smooth the communication between the phototriac and the main triac. ...
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1answer
191 views

Where should I place the capacitor in this TL431 + TRIAC crowbar circuit?

I'm building a replacement power supply for my C64 and want to add some protection against overvoltage. For that purpose, I tried to find a suitable crowbar circuit that would short-circuit the supply ...
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1answer
66 views

Controlling AC devices using ATmega8

I have an microcontroller ATmega8, TRIAC MOC3083 and thyristor M166P. I need to develop and device which will turn on/off lamp(220V). But while I'm developing I don't want work with AC 220V now, DC ...
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50 views

Snubberless TRIAC not turning on in negative cycle

I have a simple circuit with a MOC and Snubberless TRIAC. I am using the ST Snubberless Library for my simulation. I cannot understand why the TRIAC does not turn on in the negative half cycle, even ...
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3answers
160 views

Standard Relay vs SSR vs TRIAC for Switching CFLs

I'm confused weather I should go for a standard electromechanical relay (EMR) or a sold state relay (SSR) to switch CFLs @ 220V with 100W max load. This is for a commercial product with the following ...
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2answers
82 views

Lamp flickers if dimmed up to an extent

I used circuit shown in this instructable to make an AC dimmer but everything goes fine if not dimmed much but then it starts flickering because of voltage fluctuation. ...
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2answers
79 views

Using triacs to switch more complex equipment than just motors and lights?

Obviously triacs have been well known to be used in applications which don't really require a perfect sine wave to function. However, what about say a triac to switch on and off more complicated ...
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4answers
256 views

Controlling a 1000W radiant heating element with dimmers

First I would like to mention that I am a stranger to electrical components and I come from a mechanical engineering background so please keep that in mind when answering my question. I am trying to ...
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1answer
110 views

Device to switch a 220VAC/40A resistive load

I need to switch a 220VAC/40A resistive load. I only need on/off switching, no phase control. I would like to avoid mechanical (moving parts) components if at all possible because of reliability ...
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2answers
118 views

Triac motor controller

I have build a circuit with the purpose of driving a ~1000VA AC motor. The motor controller fires a triac only at zero crossings. The circuit is as follows: simulate this circuit – ...
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3answers
223 views

Light activated switch - avoid flicker when turning on

I have a small light bulb (3W LED, E27/110V) that I am controlling using based on ambient brightness (it comes on when it is dark, and goes off when it is light). The circuit uses a BT136 triac, a ...
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1answer
340 views

Design of “simple” 1000W AC motor/ heating element controller

I have been working on designing a circuit which can reliable control the on/off cycles of a 1000W (vacuum cleaner) Motor and a 1000W Cartridge heating element. It should be noted that the motor and ...
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2answers
87 views

Voltage drop across 3Quadrant triac

I am going to start off with the disclaimer that I have a Software Engineering background and very little electrical engineering background. I am using a 3q triac on a breadboard circuit. My gate ...
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2answers
201 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 ...
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1answer
86 views

TRIAC with AC plug

I would like to do a small project where I could control an AC PLUGusing a digital signal. To do that, I would need to attach a TRIAC circuit into the AC plug. All it has inside is a fuse so this part ...
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3answers
760 views

Solid State Relay Vs Triac

The general and simplified view of my circuit is something like that: Using a microcontroller I want to select between two sound signal sources (S1 or S2). S1 is a signal that comes from a ...
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1answer
76 views

Measuring the output of a phase control triac

I have an air compressor I'm trying to troubleshoot and I'm trying to determine if the problem is with a small circuit board with a triac. The board takes as input an ac wall outlet (US) and outputs ...
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83 views

Activating Triac, signal conditioning

I need help with the following circuitry. Basically it is a correction of a bug in one of my company's products, an automatic glass door controller. What it is meant to do is when I give the lock ...
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2answers
154 views

Any negatives using a Triac to transmit square wave?

I want to use a TRIAC as a switch to open a gate to transfer a 9600 baud rate square wave (for a uart communication between two avrs). Currently I'm using dc relay, but I'd like to use the Triac to ...
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335 views

Control AC load with microcontroller. TRIAC behaviour problem

As per the title of this question i'm trying to control an ac resistive load. So far i had little success and i'm experiencing "strange", to me at least, behaviour from the triac(s) i tried. first of ...
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599 views

MOC3010 & BT136 with Arduino as trigger to power AC light

I've spend days debugging this circuit and have exhausted all possible solutions. I'm trying to use an Arduino PWM pin to light a 120V AC lightbulb. In order to do this I'm using a MOC3010 ...
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140 views

Missing phase 3-quadrant TRIAC-based solid state relay for 3-phase engine

First of all, I'm a simple mechatronics technician student first time posting here, so please don't mind if I say something that seems completely stupid, since I consider myself to be a total newbie ...
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1answer
242 views

will snubber pass voltage thourgh it?

We are doing home automation project. In that we are using triac for ac switching and snubber circuit (R=100ohm, c=10nf) for its protection. Here we have inductive and resistive load, for inductive ...
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1answer
1k views

LTSpice, MAC97A8 TRIAC model, Vgs error

I'm having some difficulty getting LTSpice to like a TRIAC model. The specific error it throws is "Missing model definition for VGT-0.65". The trouble is that VGT is a subcircuit parameter, not a ...
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1answer
421 views

Controlling Triac w/optocoupler, need some help with optocoupler datasheet

Loads: Some baseboard heaters (1500W max, some motors, 12A max). I have no experience using Triacs and optocouplers. Triac: T3035H-6T, Datasheet: ...
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315 views

Problems running a triac dimmer off a UPS

I built a circuit (like the one below) to control an incandescent light bulb from an Arduino controller for the digital input. I did not use the zero crossing part of the circuit and mine is ...
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1answer
423 views

Triac and Optoisolator not turning on lightbulb

I'm trying to switch on a lamp using a microcontroller. I've wired the schematic below using a 5v power supply instead of the microcontroller for now and the first time I turned on the lamp the ...
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1answer
171 views

Triac substitute for BTA12 600TW?

Can I safely use a Triac at a higher specification than designed? e.g. for a BTA12 600TW, could I safely use a BTA18 800TW i.e. where the volt & amp values are larger than the spec?Thanks for any ...
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400 views

Using optoisolator and triac with mcu to switch light on/off--need low power alternative

I'm using the schematic below to control a lamp (light bulb) with a microcontroller and I'm running the mcu (and moc3010) off of AA batteries. I just realized the moc3010 has an LED in it that needs ...
3
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1answer
472 views

Can a triac which is driven by another triac be used for switching AC continuously?

MOC3041, BTA06 I am considering cascading two triacs like this in order to make a solid state relay. I'm not going to control the phase angle of the voltage on load as done in dimmers. I only want ...
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1answer
677 views

why does the microcontroller pin driving optocoupler is giving 2V even if it is set?

I have interfaced pin 1^1 of Atmel AT89S51 to optocoupler MOC3041 IC, I set this pin to logic high. I have connected 220 ohm resistor and red led and then pin 1 of the optocoupler and after that ...
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2answers
738 views

Heater buzzing in AC triac circuit

The problem is that my 1200 watt conventional heating element is creating a mechanical buzzing noise. Shown below is a schematic of my setup: PD4 is the output from a 5v microcontroller and is ...
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2answers
93 views

Digitally Switching a Single Source into 128 Channels

I have a device I'm building that uses a single high-precision current source (driven by a DAC for various arbitrary waveforms) to drive one of 128 channels. The current level will be on the order of ...
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1answer
501 views

Controlling multiple triacs with microcontroller for light dimming: where to use optoisolators

I want to control (dim) multiple mains lights using triacs and a microcontroller. (One triac per light). I want to keep both the costs and component count as low as possible. Is it necessary to have ...
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1answer
351 views

Isolated vs non-isolated triacs

Bt136-600 is an example of a non-isolated triac, while BTA08 is an example of an insulated triac. What is the difference between an isolated and non-isolated triac? They seem to have the same symbol ...
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2k views

Using an RC snubber with a triac. Is this design safe? (simulation included)

I'm designing an ac switch for a washing machine motor. No speed control is intended, only a switch to turn the motor on for 10 seconds and off for 10 seconds. I'm using a MOC3063 zero-detecting triac ...
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2answers
541 views

TRIAC gate resistor keeps getting burned

R85 in the following circuit keeps getting burned out when the photo-triac is turned on. It may last for a few minutes before burning out. It is a smallish 1/10 W resistor, while R83 is in DIP ...