Questions tagged [triac]
A TRIAC is a three-terminal semiconductor component that conducts current in both directions when triggered. It is often used to control high-power AC currents, both as a switch and for "dimmers" for controlling lamps or electric engines.
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3kW Heater Regulator
I want to build a triac based regulator to bring a 220VAC 3kW (measured 3.5kW on 230VAC) water heater down to 1kw, I plan on replacing triac on a fan regulator circuit to a better one but I am ...
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How to calculate PCB area size for Triac
I am using a BTA40-600B in a RD91 package to control an resistive load. My max current thru the triac will be 12 A - 120 V AC. According to the data sheet, P(W) for 12 A is 12 W. Junction to case is ....
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Triac false triggering
Hi
I am using a triac to control loads from a microcontroller. In the Triac circuit shown both R1 and R9 are connected to microcontroller. The problem is, whenever AC power supply got turned on, the ...
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What's the typical circuit for a dimmable LED light bulb?
Most common household dimmers work with old incandescent lights. They seem to use a TRIAC to "cut" some parts of the AC waveform and thus inject less power to the resistance. It is not too ...
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Controlling current through a RL load using Triac firing angle
I want to control the amount of current going through a Triac by adjusting the firing angle accordingly. The Circuit is shown below:
Let's say i want IRMS to be 0.28A then the controller need to ...
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What does it mean by Continous Current Control for a 24 Volts AC solenoid?
I have BERMAD irrigation 24V AC solenoid series S-390-3-D. Link has been attached of the product.https://www.bermad.com/app/uploads/IR_Accessories-Solenoid-S-390-3W_Product-Page_English.pdf. I would ...
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AC power failure alarm light
I wanted to make a simple circuit that shows an indicator light to glow when a load is switched OFF. When I turn OFF both the switches for the load then the indicator light should turn ON glowing that ...
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120 V AC fan motor is overheating due to speed control circuit
I am using a 120 V AC fan in my application, with a speed control circuit connected to it, and I'm controlling the fan motor using a PWM signal through software. When operating the fan at 100% speed, ...
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back to back scr circuit
I’m working on a circuit that involves an EL3063 optocoupler and a 25TTS12 SCR. The circuit is designed to control an AC load, and I've included a schematic (attached below) for reference.
Problem:The ...
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Can Triacs work under excessive heat?
I am aiming to design a UPS, however I will design the control board and get an external 2500 VA inverter and switch ON and OFF both of them using Triacs depends on the state of power if it was coming ...
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Why the Triac won't turn OFF?
I am trying to do a simple circuit includes a Triac:
it turns on fine, however the nightmare starts at the turning off point, when I turn it On and then turn it Off after 20 seconds maybe it just ...
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Soft starter for inductive loads (motors)
I am a beginner level EE working for a small company. There is a three-phase (whose only two are controlled) soft-starter project (for 1/4CV motors) that has never worked as intended. The company ...
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TRIAC Blows Off in Single-Phase Induction Motor Capacitor Switching Circuit
(Q2 is not populated)in above circuit the R11, R12 VALUE IS 360 ohm 2W, R10 is 39 ohm 2W and the c2 is 0.01uf 1000v fuse is rated 16A 250V, Q1 is BTA41600B, the above circuit use 80-100UF 250vac ...
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What is this SOIC-8 marked "BB REF / 02BU / 78GSY"?
I'm trying to identify an IC labeled BB REF / 02BU / 78GSY. It is an 8-pin SMD, in SOIC format.
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Information on JT86MB triac please
I'm fixing a pedestal fan after the motor suddenly stopped. There's a typical dimmer circuit board in series with the motor, but I am unable to find anything about the triac on it
It's a JT86MB
When ...
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No output current of MOC3021 in TRIAC Control Cirrcuit
I'm making a resistive load with control using Arduino and MOC3021 with BTA16-600 TRIAC. But I had a struggle. The output of controller is fine (I measured 5 V at output and 1.2 V in pin 1 & 2 of ...
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Problem to control contactor 380 V coil with TRIAC
I have this schematic using TRIAC BT136 600E, and MOC3023.
I want to control a contactor with a coil voltage of 380 V. The problem is that the TRIAC works without receiving a command from me, so it ...
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Turning on a 600W AC motor (PCB, circuit design)
I am looking for a bit of advice (or corrections). I need to turn on a 600W AC motor (220V 50Hz), just ON-OFF control.
I plan to use the following circuit which AFAIK it should work well for resistive ...
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Snubber circuit design for a sensitive gate TRIAC
I am designing a snubber circuit for a TRIAC used to drive an RL load. The problem is that I do not know the exact inductance of the load.
The load is a resistance comprised of wrapped wire forming a ...
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AC Motor Control with TRIAC
I want to drive an AC motor using a TRIAC. I am new to this topic. I built this circuit and found that it is not working. What could be the reasons for this?
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I need to replace this triac, will you briefly guide me?
This is the component:
G A
BCR5PM
14L9403
The only that matters is this: BCR5PM?
Any other consideration? Voltage rating? Amps? according to datasheet it supports upto 5 Amps
Last but not least, ...
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Zero-Current-Switching Circuits
I'm basically driving an AC fan from 120V AC wall power (use of classic magnetic
mechanical relay or solid-state relay is fine, but I'm weary of triacs because
of their EMI and their wasted voltage ...
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Best optotriac/phototriac for switching an inductor out of a circuit [closed]
I have the circuit below where I'm using a full bridge driver to drive an LC circuit (L1 and C1). I want to switch another inductor (L2) in and out of this circuit to alter the resonant frequency, on ...
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Should this bare minimum TRIAC circuit light the bulb? [duplicate]
In trying to build a multi-channel, optoisolated, TRIAC based, switch module, I could not even get one channel to function properly.
Trying to isolate the problem, I've reduced the circuit to this ...
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LED light bulb is flickering when switched on
I am a Physics Major student and have to do a project in our end sem.
Since we read a lot of theory and workings and very less practicals, I am a bit weak in electronics.
So here is the problem.
Our ...
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MOC3083 + replacing triac with 3Q one + no snubber
This is famous circuit from the MOC308x datasheet which many people use and refer to:
I have recently asked related question on the usage of the BT136.
I would like to understand how this circuit ...
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MOC3021M + JST16A-600B TRIAC Circuit problem: Resistor blowing up
let me clarify first than I'm no expert in electronics, so, I could be doing something really stupid here.
I want to replace the control board of my kitchen extractor motor with a custom version that ...
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Why is this light-dimming configuration flickering? Why is it not stable?
My question is why is this configuration showing an unstable flickering voltage accross the light bulb? Were incorrect capicitance values used?
Observing the oscilloscope, I note that there is some ...
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Heater circuit using series resistors
The subject seems to be very easy and simple but performing research and looking at the real devices I get more and more questions.
Let's take this article as a basis. It has the following circuit:
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Structure of a thyristor
In the test of the thyristor (BT151S-500L) that I removed from the contactor driver (in the multimeter diode test phase), I saw that the gate-cathode voltage drop was 236mV, but the cathode-gate ...
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TRIAC Controlled Motor circuit: PWM logic doubt
I'm working on the logic board of my kitchen air extractor. I wanted to "hijack" the controls (physical buttons) to be able to control those with an ESP8266. While I was analyzing the ...
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Fan dimmer using MOC3021 and TRIAC suddenly stopped working. Cannot find possible reason. The circuit worked fine for two days
I am trying to control speed of a fan using MOC3021, BT136 and zero crossing detector. The circuit worked fine for 2 days and then suddenly stopped working. I am unable to find the problem in the ...
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Triac flickers when I apply main power
I am building an ESP32-based AC mains power switch by using TRIAC BT136-600D (common triac).
My first issue is my load didn't turn off the load (lamp) properly at 30%-40% brightness, and when triac ...
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Protecting Triac + Relay from surges
I am having 3 triacs and 3 relays that are used to control heater elements in triangle configuration. Atleast the triacs need some kind of surge protection since they can only handle 800V and surges/...
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What is the purpose of diodes on the gate of a silicon bilateral switch (SBS) TRIAC trigger circuit
Here is a typical TRIAC SBS trigger circuit to control a resistive load. This example is from the BS08A datasheet but there are plenty of others.
What is the purpose of the D1,D2 and R3? It appears to ...
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What is a bridge rectifier doing in this TRIAC regulator?
Recently I purchased a TRIAC-based mains regulator and took a look inside. It's a very typical TRIAC regulator, except it contains a bridge rectifier (DB207S), the purpose of which is not clear to me ...
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Troubleshooting Vacuum Roller Motor
I am trying to repair a vacuum so that the carpet roller will work again (motor does not run). I have disassembled the head of the vacuum and found what is probably a fairly simple electronics board ...
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What is this glass bulb containing three parallel electrodes?
I'm trying to figure out what the glass component on the PCB is. Maybe some sort of vacuum tube? Maybe a triac? It's got three leads, and appears to have three parallel electrodes inside the glass ...
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Can a MOC3032M optocoupler be used to generate a DC PWM signal?
I'm trying to make a circuit that can output an 80 Hz PWM signal. I'm planning to use an Arduino to switch an optocoupler that will control the duty cycle.
Here is my circuit:
After building the ...
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How on Earth can a solid state relay be constructed?
Relays are very handy components. Relays allow current to both directions on the controlled load circuit so they can be used for both AC and DC. However, relays have a finite lifetime if connected/...
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RCD snubber circuit
I'm designing a timed fan switch using an 800V 25A (overkill) TRIAC with an RCD snubber circuit with 120VAC source. The circuit is shown at the TRIAC shut off at I_hold of 50mA. The load current at ...
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MOC3021 stopped working
I am trying to make a dimmer circuit using an MOC3021 and a BT136.
I used a zero crossing detector with a 4N35.
The dimming is controlled with a processor.
Initially the circuit worked fine, but ...
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TRIAC controlled fan output on furnace control board not working
At board power-on, the fan output connector has mains (230V AC) voltage without the fan connected, that drops to ~2V AC with the fan connected.
At power-on, on the attached display, the board shows a ...
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Triac dimming light is affected by other non dimmable load (relay)
When I am using one dimmable light turning on/off is working OK and dimmable is OK.
But when I’m using other non-dimmable load turn on/off through relay, then dimmable light is on/off for the 1 s.
Is ...
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TRIAC driver circuit - MOC3021
I have created a TRIAC AC dimmer circuit using an MOC3021 and I am facing the problem that the output is always on.
Please help me rectify the issue.
Please see the image of the circuit and Zero PCB I ...
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Schematic of a simple zero-crossing triac switch
I have a triac in a 60Hz 120V power line (as is often done for dimming)
and want it to only switch on the power when the AC voltage is low
(widely between -40V and +40V would even be fine).
This is ...
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Triac Not Triggering in Q3
I tried simulating this circuit in LTSpice, but, if I'm interpreting this correctly, the triac isn't triggering in Q3.The gate current reaches -360mA when I would expect the triac to enter Q3.
I'm not ...
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What's the circuitry inside triac driver optocouplers?
When looking through datasheets I can't find a single one that shows the inner circuit of a triac driver optocoupler, all I get is this common diagram:
What that zero crossing circuit looks like? how ...
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How to Get Started with Triacs
I'm interested in building a solid state relay module at home using a triac.
I know the safety risks associated with this project. I'm also aware of the cheap SSR modules capable of the same things. ...
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