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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Solid State Relay with BTA41 600 and MOC6063 [on hold]

I'm new to electronics, I'm trying to make SS relay with Triac BTA41 600 and Optoisolator MOC3063 but it doesn't work !! I tried the circuit in the data sheet but it keeps the triac on Any suggestions?...
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49 views

An SPDT switch using TRIACs

I need to design a circuit that implements an SPDT switch using Triacs and Optoisolators. Currently I am implementing this with two pairs of Optoisolated Triacs with one having inverted signal from ...
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86 views

Can anyone give me tips on how to proceed with this triac/optocoupler/motor circuit fix?

I'm working on a Fisher Digital Vortex Mixer that has an intermittent issue in which the AC motor is energized, but no movement occurs. By rough estimate, this will occur on one of every 8 attempts. ...
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25 views

Read Thyristor(Triac) specification

I have this Triac which I believe is failed because of a hight current we had in the house. The varistors that were next to it were totally burned. I am trying to buy some online, but I really don't ...
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61 views

Why are the wires of thyristors always twisted in pairs?

I have always been told that you should never untangle the wires of a thyristor or subset of thyristor (such as TRIAC and SCR). Why is this? Is this just for convenience or is there a use for the ...
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73 views

Can I use a Triac dimmer circuit to control the brightness of an AC powered LED light strip? [closed]

I am using this Triac circuit to control the brightness of several incandescent lights. The circuit monitors the phase of the 120 volt wall current, then signals an Arduino when the phase crossed ...
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37 views

Problem in AC fan speed control(using ZCD and Atmega8A) when running on Inverter

I recently built an AC fan speed control circuit using Atmega8a,Triac,2 nos Optocoupler and ZCD method.I am attaching the necessary circuit regarding the triac firing and ZCD.The Atmega is configured ...
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34 views

Triac drivers with or without zero-crossing detection

I've been looking at this schematic for triac control by varying the gate pulse timing. The description states that the triac switches off automatically at zero crossing and when there is no gate ...
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90 views

SCR “current gain” - calculating gate resistance

Trying to understand the SCR. Have made this outlay which I shall find the right resistors for. edit or The SCR is a TYN1225 But since I have found it difficult to understand \$I_{GT}\$ and \$...
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25 views

triac switch with two power suppllies

I'm building a furnace controller that should hook up in parallel to a home thermostat. The schematic of a thermostat-controlled furnace (omitting non-essential components) is below (Fig.1): I would ...
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67 views

What is the relation between the mains frequency and the ideal PWM frequency in this circuit?

Below is a triac control circuit used in on-off mode: The mains freq. is 50Hz. The micro-controller PWM frequancy is set to 5Hz in this simulation. Optotriac is triggering the triac. By playing ...
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Confusion with TRIAC firing and zero crossing point

The reason for firing a TRIAC very close to the zero crossing point is explained as to avoid RF or EMI interference. Below is an excerpt from a book: What I'm having trouble to understand is that, ...
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65 views

Questions about a dimmer circuit

Below is a simple dimmer circuit using a triac, a cap and resistors. As you can see, the resistor Poti changes with time and the load current change can be seen in the plot. It seems like one can use ...
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45 views

Triac connected CFL or Incandescent bulb or Electronic ballast tubelight FLASHES

I am building a triac based dimming circuit. Everything is working fine. The problem which I am facing is when I turn on or off any appliance (NOT CONNECTED TO TRIAC) in my any other room, the ...
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3answers
84 views

Latching triacs

I want to trigger a triac on or off by setting pulses instead of a constant gate voltage. The idea is that you provide the initial gate current for a short time and then somehow the triac keeps itself ...
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148 views

Zero-Cross detector problem

I am really in a tough situation and need very serious elaborative help with this. Almost like spoon-feeding. It's been days I've been trying to get my zero cross detector (and the triac dimmer) to ...
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1answer
39 views

Why does a triac trigger with gate current in either direction?

I've been coming up to speed on thyristors, and triacs in particular. I've found detailed material on them a little hard to find, in particular on the device physics. Horowitz & Hill is silent on ...
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37 views

Triac Datasheet/Design Questions

1) How do I choose the resistor for a triac? I saw this design in the opto-isolator datasheet that I'm using. I thought I'll just change the resistor value based on the gate characteristics of my ...
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68 views

Is a “self-bootstrapping” zero-crossing AC power switch possible?

As a follow-up to this prior question I'm looking for a zero-crossing mains (120V) power switching solution to mitigate the bounce-related EMI I'm getting using the "stock" traditional ON/OFF toggle ...
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80 views

Dimmable AC LED controlled by Arduino

I am a beginner, and I have a school project that requires me to use Arduino or any other microcontroller to control an LED light. After some research, I found out that not all LEDs support dimming, ...
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128 views

TRIAC Angle of Firing vs Power Delivered to Load, how calculate?

I'm building a phase control system for simple power control to a given load (heater for example). I need an equation to find the relationship between angle of TRIAC firing vs power delivered to load ...
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382 views

Why do we bother with SCRs?

As far as I know, SCRs are basically the DC-only cousin of a TRIAC. However, in my travels I have not encountered a TRIAC being much different in price than a similarly spec'd SCR, so I guess I don't ...
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99 views

Controlling 5V Pushbutton switch fails with Triac

I have an external consumer product what I try to automate by connecting my Arduino to its push buttons. This device uses internally 5V, I can get this voltage on the switch buttons as well. My ...
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39 views

Spoofed solar grid-tied system load management

Thanks for having me in your midst. I am new at this site. The situation I am designing for is thus: My 5 kW solar array has a micro inverter on each panel. When feeding into the grid, the ...
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26 views

Problems when dimming triac with load have large capactive

I'm make a circuit to dimmer a led light bulb base on zero point crossing detect. But I have a problem with load, the led light bulb using RC type power supply to drive a string of led series. I think ...
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136 views

Difference between optoisolator(optocoupler) and solid state relay?

I have been looking into relays and optoisolators. I am aware that there are different optoisolators, with some having a transistor on the detector side which allows current to flow in one direction ...
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132 views

Working of optoisolator MOC3041 & triac connection

1) Pl help me with the working of optoisolator MOC3041 & MOC3020. Also its use in ac dimmer apart from isolation 2) Also as triac(BT136) are bidirectional how does the term "reversed" ...
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116 views

AC dimmer- triggering triac using moc3041. lamp always remain on, and does not change its intensity

Below is schematic. 1) Problem is lamp always remains on,even if i haven't provided the Anode A terminal with power through micro controller. 2) Also please explain me the need for R7 resistor. 3) ...
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70 views

How do I control this power circuit using an MCU?

I'd like to use this heater element for a project I'm working on. It looks like a good product but there is unfortunately not much documentation available, but I think it's basically a simple ...
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40 views

TRIAC Circuit triggered due to interference

I have a small circuit designed to switch on the lights in my room using a wifi-enabled microcontroller Particle Photon. The circuit is based on an opto-triac and TRIAC setup where the microcontroller ...
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19 views

TRIAC randomly (momentarily) switches on

I have a small circuit designed to switch on the lights in my room using a wifi-enabled microcontroller Particle Photon. The circuit is based on an opto-triac and TRIAC setup where the microcontroller ...
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89 views

Using AC current to trigger Triac

I am trying to simulate the operation of an optocoupler with a triac to trigger the triac using the AC current. I have come across a few circuits that are all similar: My question is regarding the ...
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43 views

Using Triac to control solenoid

I have to design a 4 relay or 4 triac switch. First would control a 12V solenoid for water flow. Second would control 230V for a complete device which contains a small boiler as well. After reading ...
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128 views

What are the risks of powering fan AC motor with Triac dimmer?

I'm going to replace current resistor potentiometer with arduino-controlled triac scheme, probably this module. I'm going to load it with 6 motors , 300W each. How bad the EMI gonna be (would I be ...
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255 views

Triac spurious triggering issue

I have a circuit where I am using triacs to switch home appliances like fan, tube light etc. This is the circuit I am using: (TRIAC1, TRIAC2, TRIAC3 come from arduino GPIO pins) First load is a ...
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87 views

Spurious triggering in TRIAC due to EFT

I am working on a project to control AC load using TRIAC In normal operation it working complete fine But when a fan regulator specifically step type capacitor regulator is used in vicinty the ...
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37 views

Should serial triac dimmers work for resistive load?

I have a cheap 120V hot plate that I assume regulates its temperature using a triac dimmer (because the heating element vibrates/hums at lower settings). But at its lowest setting it still gets too ...
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161 views

switch for AC voltage

I am designing a switch for AC circuit. E.g. when I apply a small DC voltage, AC current is allowed to conduct, otherwise there is huge resitance stop the current from flowing. I found 2 possible ...
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121 views

Triac BTA316 does not turn off

I had a look to other posts about Triac and I am pretty sure my problem was not in there. The goal of my system is to realized a controlled switch for home appliance. Then I designed a power supply ...
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98 views

Power rating for opto-triac trigger circuit resistors

RHS will be using 220v 400watt bulb 2 simple questions 1- does the 360ohm resistors has to be of high watt too ? 2- all i can find is 5-10watt resistors, can i use them ? would they snub correctly ? (...
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What is the intended use of high current SSRs and triacs?

I answered a question recently regarding power dissipation in solid state relays. This is the calculation: Consider this 40 A rated triac - BTA40. Vto = Threshold voltage = 0.85V = Voltage drop ...
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123 views

Can I use a TRIAC on a secondary isolated AC winding?

Can a TRIAC be used on the secondary winding of an AC isolation transformer? Say I have 230 V on the primary, but I want to use the 12 V AC secondary, will a TRIAC work on the secondary? ...
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180 views

Light dimming regulator circuit

Here in this circuit, We have the load connected to a diac and triac circuit along with a variable resistance and a capacitor. When the circuit operation begins initially, the energy is stored in ...
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67 views

What to use to switch AC power supply using 5v micro controller? [closed]

Here is my question and situation in more details. I am working on a college project where I need to switch on/off AC appliances using 5v Micro Controller. Appliances can be fan, motor, Fridge, Air ...
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2answers
121 views

How do I gate a z0103ma triac using logic level output?

I'm trying to switch an el wire segment on and off by using a z0103ma triac. I have the AC current connected across pins 1 and 3, and when the gate is closed, the ac current is interrupted, but once I ...
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230 views

How to design a 2 way switch using Triac and SPST standard switch?

I have a triac which I turn ON and OFF by giving a gate pulse through microcontroller. With the help of triac I turn ON/OFF a light in my bedroom. The bedroom light is connected to a standard SPST ...
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3answers
149 views

Automatic calibration of a zero cross detector latency

I have a circuit similar to this one (different component values, different uC): I expect a large phase error in the ZCD. The load is purely resistive and of unknown value between 100W and 1000W. ...
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2answers
210 views

Triac-Diac Dimmer build

I recently bought a DIY 1000W AC motor dimmer meant to be powered off 220-240VAC. I was hoping to use this to control a transformer which in turn powers a heating element. The heating element needs ...
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2answers
255 views

Using zero crossing detector for brightness control of several loads

Zero cross detector(IC H11AA1) generates a pulse exactly at zero crossing of AC wave. I am trying to control the brightness of several bulbs(nearly 48 loads). I have 5 different states for them. At ...
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69 views

Question about Triac vs Rlay [duplicate]

I am a software developer with little knowledge of Electrical Engineering. I have delivered some Raspberry PI projects that extensively use Relays. I recently heard that Triacs are much cheaper and ...