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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How do I get proportional 240V AC output from an Arduino-based PID controller to “dim” a rice cooker for a Sous-Vide project?

I'm making a PID controller for Sous-Vide, using an Arduino. I'm trying to decide how to control the output. Using an SSR as an on-off switch on 240V AC will probably give me the result I'm looking ...
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How do I drive a TRIAC from a microcontroller (for low voltages)?

As a followup to this question, I would like to figure out how exactly one might go about driving a TRIAC from a microcontroller (for low-voltage applications, such as 24VAC). Imagine a scenario where ...
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What would a professional use to switch sprinkler solenoids?

As evidenced by several previous questions of mine, I'm working a project to design a sprinkler controller. This involves driving one of 16 solenoids (well, probably only one at a time...) based on a ...
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Trouble with triac driven dimmer circuit

I have a dimmer circuit that produces the following wave forms. Red: Triac Gate Signal Yellow: 120v 60Hz AC Wave (not triac output) I would assume that given this signal, the triac should flip on ...
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Troubleshooting a Triac Motor Control Circuit

I have a Xytronic 988 soldering station. It has a regular soldering iron on the left and an iron with a vacuum pump on the right. It has served me well over the years and one day when I was swapping ...
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Arduino triggering a TRIAC for EL Wire, no optoisolator

I have been researching and looking up how to control EL wire online and I will be using the same layout as the EL Escudo shield from Sparkfun but just for one strand. Basically: Arduino (+ resistor) ...
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Optotriac doesn't turn off

I'm using an opto triac, specifically the MOC3041, with a zero crossing circuit to switch the Tx pinout on an RS-232 interface. I have no problems turning it on, but after I unload the input (no ...
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Modding a dremel to accept 230volts

I purchased a Dremel tool from the United States and using it in India. As always, the trouble is with the power inputs. A step down converter is simply too expensive for those power ratings (>2 Amps ...
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Looking for and SMD optocoupled TRIAC

I'm looking for a SMD optocoupled TRIAC part for driving EL Wire (110VAC, 1000Hz, low current non-resistive load) with an ATTiny85 pin (TTL, 20mA max) running at 3.3V. The previous design used the ...
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SSR vs optocoupler with TRIAC output

I've designed (and mostly implemented, now) a system for turning on and off 24VAC solenoids. In order to achieve this, I used optocouplers with TRIAC output (Sharp PR26MF1xNSZ series). The datasheet ...
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When should I fire the TRIAC's gate when controlling an inductive load (AC motor)?

I'm using a combination of opto-triac + TRIAC to control a 230V AC motor with a microcontroller. For detecting the zero-crossing of the voltage I'm using another optocoupler. I know that the AC ...
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What does 'random phase' means in a triac driver?

I'm using this triac driver to control a triac. In its datasheet it says 'provide random phase control of high current triacs [...]'. What does that mean? It doesn't have zero-crossing detection?
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Is a protection diode needed on a TRIAC optocoupler and what for?

Please refer to page nine of the Sharp S108T01 / S108T02 datasheet: Is this diode needed - why/why not? How do I choose the correct diode, if yes? UPDATE: Thank you all for your educational ...
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Difference between Zero-Crossing Optoisolator and Regular Optoisolator

I am trying to find any documentation on what the purpose is of a Zero-Crossing Circuit TRIAC Optoisolator. The datasheets don't explain the concept well enough. If you do answer, please include ...
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How to calculate minimum gate current and voltage of a TRIAC

I want to use this TRIAC: http://www.littelfuse.com/data/en/Data_Sheets/Littelfuse_Thyristor_Lxx06xx_Qxx06xx_Qxx06xHx.pdf but only the maximum Igt and Vgt are given (25mA and 1.3V). How much ...
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Choosing components for a triac's snubber

I'm interfacing the BT139-600 TRIAC with this MOC3051-M Opto-triac. I want to build a snubber circuit for the TRIAC as shown in the MOC3051M opto-triac's datasheet @ page 8, figure 12. The load ...
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TRIAC heatsinking

I am thinking of using a BTA04 type TRIAC in a project to switch a power hungry mains appliance, which could draw up to 12A. I can't find a forward voltage anywhere in the datasheet, or an on-state ...
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Triac Turn-on Stress Calculation

When snubbing a triac, one of the concerns is minimizing turn-on stress as your snubber triac discharges across the newly-shorted terminals of the triac. This paper says that the main concern is ...
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Sanity-check on snubber design

I keep frying resistors in the following optocoupler and triac snubber circuit, and I'm not sure whether to attribute this to bad design, or to faulty components. There are no observable sparks at ...
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Using a triac to switch on/off a single phase AC motor

I want to use a triac controlled by a suitable optoisolator such as a MOC3020 to switch a single phase AC motor on and off, like the ones you'd find in a typical desk fan or a blender or similar. I ...
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Why Snub an Optoisolator?

I am using an optocoupler and a power triac to switch 120VAC supply to an ~108 watt fan. The datasheet for my optocoupler requires me to snub the optocoupler output when I'm switching an inductive ...
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Current limiting at mains voltage

I am driving a BTB16-600BW triac using a MOC3052 exactly as suggested in the MOC3052 datasheet: The current into the power triac gate is limited using the highlighted resistor. My triac requires at ...
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How to use a phototriac coupler to trigger the main triac?

I have in my box of parts a phototriac coupler, namely a Sharp PC3SD21NTZ (datasheet), which is a zero cross type. I don't know how to use it, but I've been meaning to learn for a while. This part is ...
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What's the difference between 3 and 4 quadrant triacs?

I'm looking at triac datasheets, in particular this datasheet for BTA16 series triac. The "electrical characteristics" section is split into two parts: snubberless/logic level (3 quadrants) and ...
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Are TRIACs symmetrical?

When debugging a circuit using a micro-controller and triac to control AC current I ran into an issue (the triac wouldn't switch off) that was only resolved by flipping the polarity of the triac. The ...
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673 views

Microcontroller + Triac without an optoisolator

I have a project that needs to be in use on saturday (afterwards I'll be able to complete it properly) and my optoisolators haven't come in yet. I'm using an arduino to switch mains power (on/off) ...
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Controlling water pump speed

How can you control the speed of an AC water pump? In particular this one. My guess is that PWM won't work on an AC motor? I've heard that controlling the voltage will change it's speed...is this ...
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Triac versus Relay

What are the scenarios where Triacs can not replace a relay or vice-versa?
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Controlling High Voltage device with Arduino

I want to control lava lamps using Arduino. I think it shouldn't be hard project, but I have no experience with hardware projects so I'm not sure witch design will feet best for me. I consider using ...