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.

learn more… | top users | synonyms

0
votes
1answer
26 views

What happens when triac terminals MT1/MT2 are switched?

According all literature, terminals MT1/A1 and MT2/A2 must be connected to neutral and phase respectively. What happens if you reverse the wiring? House sockets here are randomly wired, so it's a ...
0
votes
0answers
32 views

Drive several triacs

There are several projects with triacs for cargo, including drives with use of it in parallel (which I don't recommend), but mine is the following: I'm replacing the triacs by lowly switches to that ...
0
votes
0answers
36 views

Short-circuit when switching off TRIAC circuit

I'm developing a circuit to control electric lamps using a TRIAC. I tested the circuit and it can switch on and off the lamps without any problem. For tests I'm using a regular light switch to cut the ...
1
vote
1answer
39 views

Digital replacement for Rotary Capasitor based fan speed controller

Is there a circuit using Triac and capacitor in series to control the speed of ceiling fan? There is a circuit using SSR but I wish to use Triac as SSR are bit costly. ...
1
vote
1answer
59 views

Triac fails unusually

The circuit is a MCU triggered, capacitor based fan speed controller. The circuit works fine when a single triac is connected but when both triacs are wired and triggered alternately, any of the ...
0
votes
0answers
18 views

DIY Mains Power Distribution

I am trying to create a product unit with an enclosed microcontroller that can function like a WiFi-enabled bulb (albeit with an entire enclosure and an enclosed audio speaker). I am a total beginner ...
0
votes
2answers
67 views

Braking a motor commanded by an IC H-bridge

Firstly, some premises of the design are related to the high speed needed (maximum as possible) and precise stop point. The motor is feed at a maximum of 40V and consumes at normal operation 1.5A. Due ...
1
vote
1answer
34 views

Better triac gate configuration

I'm an intern who was tasked with finding a way to switch on a motor and solenoid from either 120 or 240 VAC. The circuit on which my supervisor suggested I base my design can be seen below. My ...
0
votes
3answers
110 views

Optoisolator with EL wire won't turn off, TRIAC works fine. Why?

I'm pretty new to electronics, and I'm making a circuit to control EL wire with a DC logic control signal. Specifically, I would like to blink the EL wire with the output of a 555 timer. My first ...
0
votes
1answer
56 views

Parallel TRIACs driving same load

I am designing a series of heaters. One of them, actually, is designed for 220V and uses two resistors on series to achieve the power desired. The total current is, on peak, almost 20A. To keep the ...
0
votes
1answer
55 views

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 ...
0
votes
1answer
30 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 ...
-1
votes
1answer
39 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?
0
votes
1answer
46 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 ...
-1
votes
1answer
43 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 ...
0
votes
0answers
47 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 ...
1
vote
1answer
63 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 ...
0
votes
1answer
33 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 ...
1
vote
1answer
77 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 ...
1
vote
2answers
84 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 ...
1
vote
2answers
94 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 ...
1
vote
1answer
62 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 ...
0
votes
4answers
56 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 ...
0
votes
3answers
76 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 ...
0
votes
1answer
127 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) ...
0
votes
1answer
117 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 ...
6
votes
1answer
824 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 ...
-1
votes
1answer
62 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 ...
0
votes
0answers
1k 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 ...
1
vote
1answer
187 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. ...
1
vote
1answer
125 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 ...
1
vote
1answer
143 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 ...
0
votes
1answer
84 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 ...
0
votes
2answers
102 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 ...
0
votes
1answer
64 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 ...
3
votes
2answers
140 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 ...
2
votes
1answer
221 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.
0
votes
1answer
354 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 ...
6
votes
2answers
200 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 ...
0
votes
1answer
289 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 ...
3
votes
1answer
231 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 ...
1
vote
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 ...
1
vote
1answer
133 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 ...
0
votes
1answer
562 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
0answers
247 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
264 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 ...
4
votes
2answers
339 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 ...
0
votes
6answers
1k 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. ...
1
vote
2answers
202 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 ...
0
votes
1answer
68 views

triac DC ground and AC live

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