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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Can someone verify my EL wire oscillator?

I'm pretty new to electronics, but my latest project is a circuit with two "frames" of animation that I make out of EL wire, and I want to build a circuit to switch between them every 2-3 seconds or ...
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24 views

Gate controlled turn-on time

Under DYNAMIC CHARACTERISTICS for BT137 is Tgt value set to typically 2us. If I then look under BTA16, I see no mention of the pulse width. Is there a minimum pulse width as a standard value for all ...
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34 views

Sensitive or not sensitive gate? [closed]

If there is nothing about it in the datasheet, how can I find out if it is a sensitive or not sensitive gate?
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36 views

Difficulty understanding data over opto-diac

I'm having difficulty understanding the data over MOC3021, DIAC side. Should I see it as with DB3? So DB3's \$V_{bo}\$ (28-36V) is the same in opto-diac, and DB3's \$V_o\$ (min 5V) is the same as ...
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36 views

How is it possible to use TRIAC dimming with an 110v input LED T-8 Tube light?

I have seen T8 or T10 Led Tubes made for entertainment lighting that can plug into a Triac dimmer and be dimmed down to approx 10% with no flicker and no color shift. Attached is a picture of the ...
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17 views

Integral cycle (PWM) control of AC voltage input to heater

I'm designing an open loop voltage controller for my water heater element. I'm planning on using a triac and controlling it using integral cycle control. There is no temperature sensor feedback , just ...
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1answer
40 views

Switch high frequency AC on/off at zero crossing

I have a 3 phase generator which is powering some system. (50Vrms @3A, with variable frequency from 50-5KHz). I've used mechanical relays to control each phase to the load. However, there was no real ...
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29 views

TRIAC controlled fan voltage issue

I have a question that seems to baffle electricians that I've spoken to. I'm running a 115V Fan off a TRIAC controller that utilizes a 0-10VDC control signal. When I power the DC control signal ...
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1answer
41 views

Question regarding a resistor in optocoupler/TRIAC circuit

I'm building a ac motor starter with a optocoupler (FOD4218) and a TRIAC (BTA16), one for each phase in a three phase 400V system. I have a question regarding the circuits that can be found all over ...
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2answers
41 views

Parallel TRIAC's for greater heat dissipation

Is it possible to parallel TRIACS to lower heat dissipation per device? If so, what would be the best strategy to ensure balanced current sharing between devices? The target application is to switch ...
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1answer
41 views

Triac - opto-coupler Circuit Confusion

I have the following question regarding this circuit: How is the opto being used to trigger the base of the triac?The collector of the photo-transistor is connected to the base of the triac. As per ...
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1answer
49 views

Considerations when repairing dimmer switch

I originally asked this question on DIY StackExchange. So far no answers and a suggestion to try on Electronnics, so here goes: I have an IKEA lamp with dimmer switch which took a knock and ...
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4answers
48 views

230V AC Wave forms in an analog ocillocope

I was doing a project on AC Phase control using triac,and I needed to see the phase controlled waveforms in a scope.But the scope that I am using has maximum volts/div as 5V (found on many scopes as ...
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3answers
46 views

Live switching AC loads with TRIACs or SSR

I have been designing a system whose purpose is to provide high reliability to a set of outlets (8), it takes to inputs of diffrent phases mains current, now the purpose of the system is that if the ...
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1answer
100 views

triacs from dishwasher

I have PCB from broken dishwasher and I would like to learn something from it. There are 6 smaller - STMicroelectronics Z7S, 1A triacs and one bigger STM T4 3570. My guess is (cannot verify it now) ...
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72 views

Power supply for an irrigation system

My irrigation system control box just died and I'd like to replace it with a smart controller based on a Spark Core programmable board, so I can monitor temperature, soil moisture, humidity, and other ...
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1answer
307 views

how does the circuit of a basic Variable speed electric drill work?

i am trying to 'automate' the control of an electric drill motor that im taking from a garden variety Variable Speed drill (from Harbor Freight) it has a universal AC motor which I basically ...
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1answer
50 views

Traic switching in 3+ quadrant

I am controlling fan speed using Triac phase control with a circuit similar to this. The problem that i am facing is that my triac burned out after using it for 2 3 days and after burning it will ...
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561 views

AC fan speed control (using Arduino)

I wanted to control a 220V, 50Hz AC ceiling FAN using PWM output from an Arduino microcontroller and I have referred to several resources regarding this. Resources I referred ...
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1answer
124 views

Why do we prefer zero-crossing optotriacs for driving triacs?

I usually see a special type of optotriac which has internal zero-crossing detection circuit in it. This type of optotriac is generally used for driving triacs. But, I don't understand its necessity. ...
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1answer
63 views

How to correctly simulate Zero Cross Detector Circuit?

I am trying to simulate a circuit for Zero Cross Detection. The end goal is triac phase control. My simulation using proteus hangs up and with message "Simulation is not running in real time" and ...
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1answer
117 views

Wired Or of Triacs don't seem to work

I am trying to make a full sine wave from two half waves wire-ORng through triacs However, as long as the triac output terminals (MT1 for both) are not shorted, the signals seem fine. When I short ...
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72 views

High Voltage Triac Control

I'm trying to control a universal motor run from a 240V power supply using a micro-controller. There is a existing PCB that uses a potentiometer to vary the speed that I am trying to replace. I've ...
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2answers
87 views

Triac circuit confusion

X1Iz.png I have the following questions about the above circuit: -Why are we even using a trica/diac combo above. Why would a circuit consisting of just the fuse, switch and primary not be ...
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49 views

Switching 150kHz mains for an LC load

I'd like some input on whether or not to use a mechanical relay or some form of SCR setup to change the capacitance in my LC circuit that is currently operating at around 170V, 1A at 150kHz. (Not ...
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2answers
115 views

Arduino Dimmer Shield Schematics Interpretation

I've read so much about Thyristors, Triacs and Rectifiers on the last days that I'm almost understanding my schematic, but I'm not there yet - I need some help. Overview: I'm making a home automation ...
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1answer
154 views

Why do we use a diac for triggering a triac?

I mean, Wouldn't it be possible to give a gate pulse on triac directly? I have seen in many phase control application circuits like fan speed control,the usage of diacs to trigger a triac.
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269 views

Short circuit protect for Triac

I'm going to use this circuit to control some lamps. As I know a short circuit would cause the Triac to burn very fast and I need a way to protect it. Using fast fuse is cool but I need to know If any ...
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172 views

Turn a mains light on slowly

I've been looking at creating a simple circuit to slowly turn a halogen daylight bulb on over about 30 minutes as soon as power is supplied to simulate dawn. I've got a 240VAC 42W halogen bulb that ...
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1answer
220 views

Will replacing the MOC3024 with MOC3021 make any change

I'm student of 10th grade and new to electronics I'm trying to make a switch to control appliances which runs on AC mains and I don't want to use any relay see the circuit diagram from the link to ...
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1answer
190 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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2answers
1k 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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119 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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407 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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209 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
216 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
292 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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6answers
758 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
194 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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63 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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267 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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497 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
551 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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119 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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82 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
350 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
112 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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91 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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913 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
165 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 ...