Questions tagged [diac]

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53 views

TRIAC BT136 as DIAC BD3 conversion both have MT1 and MT2

A DIAC looks like a diode. A TRIAC looks like transistor. I have project that uses a DB3 and a BT136, but the BD3 is not available in the local market. Can I cut the gate terminal off of a BT136 to ...
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1answer
42 views

TRIAC Voltage Control

I have the simple Triac voltage control circuit. The values of resistance and capacitor are 10k and 0.1uF respectively. I want to know that the following. 1- How can we calculate these values of ...
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2answers
76 views

Light dimmer not working

I made a light dimmer from this circuit below but doesn't seem to work. It seems to work with vloggers online but they are using 220V mains, I'm using 120V. I'm guessing resistors values may be the ...
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1answer
60 views

DIAC datasheet's circuit is not in series with TRIAC's Gate

Being my first time to use a Triac and a Diac to control an AC signal, I read many questions/answers in this forum related to DIACs controlling TRIACs, all being very helpful. Now, I see in a MOC302 ...
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2answers
54 views

How is Gate Trigger Current determined in a "dimming" circuit?

EDIT: DIAC part numnber is DB3TG I'm trying to understand how a dimming circuit works, specifically TRIAC control. The TRIAC (D1) in this circuit is a BT136S-6. Where does the Gate Trigger Current ...
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1answer
49 views

A question on thyristors and phase control

High schooler here reading on thyristors. Videos online and books say they can be used as light dimmers. I assume that's because we can control the amount of current that can enter a load. But what ...
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0answers
52 views

DIAC in series combination?

I wanted to make a cheap and simple high voltage protection circuit which can turn off my appliance for 10 sec when high voltage hits. Generally DIAC works on 30volts. I have dozens of these DIAC I ...
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0answers
55 views

How to explain how the DIAC and TRIAC works in a digitally controlled fan regulator circuit?

There are two version of the circuit that do the same thing. One with capacitor, and, one without. The schematics below depict the circuit needed for diac/triac activation properly. (I have missed out ...
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1answer
94 views

Designing a triac based regulatable DC supply

I need about (30V-160V)32A DC for my project. I am trying to build an electronic circuit to regulate AC mains (220V, 50Hz) to produce voltage from 30V to 160V and rectify it to produce DC voltage. ...
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1answer
473 views

Simple DIAC circuit which I do not understand - LTspice

Here is the circuit : Here is the model and the parameters of the DIAC : ...
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1answer
180 views

This Potentiometer Keeps Catching Fire And I Can't Locate The Short

Device: KADA 852 Hotair rework station (not 852D) VR9 keeps catching on fire and R42 is half toasted but still keeping its resistance, I removed and checked CA12 and CA13 and they are not shorted. ...
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2answers
483 views

How DIAC works?

I edited my whole post for more refreshed information I learned about DIAC. Let's consider the following circuit and how it works. First of all the Vs must be higher than break voltage of diac, so ...
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2answers
591 views

Capacitor in parallel with relay coil backfires on contacts

I've got a smoothing capacitor(2,2uF) C1 in parallel with relay coils inside a fullwave diode bridge. When the circuit is closed through contacts in pre-relay RLY1 it first gives me, almost everytime ...
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1answer
105 views

Triac control circuit through load

Why is it that in every triac analog dimming circuit I find that the triac triggering circuit is fed through the load and not straight from the mains??
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1answer
356 views

Questions regarding eliminating hysteresis in ac dimmer

In the following circuit it says: “This hysteresis effect can be eliminated however, using the circuit from a detailed application note from Littelfuse shown in Fig. 6.4.4. Here the capacitor C1 is ...
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2answers
207 views

High(er) Current AC Flasher Circuit

I'm trying to develop a flasher circuit for an aircraft warning light like the one shown at https://flightlight.com/products/obstruction-lights-controls-faa-l-810/. The light will be powered with ...
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2answers
3k views

110V sewing machine plugged into 220V - DIAC blew?

Our 110V Brother sewing machine got plugged into the 220V side of our step down transformer. After a short pop, it does not turn on. I pulled the power supply board out and it seems like just an input ...
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7answers
4k views

one-way AC power

Is there a device to only allow AC power to "flow" one-way? Scenario: I have a circuit in which I would like to draw AC power from two sources: One source is good ole wall (grid) power and the other ...
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1answer
2k views

SCR triggering using DIAC

I've found this method of triggering of the SCR through DIAC and I'm trying to understand it. I was able to figure out the whole trigger circuit and how to compute the values of RC in order to have ...
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2answers
2k views

Two or more Diac Triac dimmers in parallel

I wanted to know whether connecting two or more simple diac-triac ac lamp dimmers in parallel with the same load cause any problems? I do not want to connect them in series, just parallel will be ...
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3answers
8k views

Zero crossing detection and Light dimmer

I am confused by zero crossing detection of opto-triac. I know what is the zero crossing detection or switch. (ZCS) Zero crossing detects what is the point that wave is going to positive to negative ...
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0answers
543 views

What is the correct method for Triac supply?

I need to know what is the correct power supply for fallowing light dimmer circuit that operate by 230V/50Hz AC supply. It should be neutral(N) to MT1 or live(L) to MT1? If can use both, what is the ...
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2answers
467 views

Can someone help me understand DIACs and TRIACs

These are something that has confused me for quite some time. Just like a lot of you, I'm sure, I'm a tinkerer. I like to take things apart, salvage parts, etc. A lot of stuff I take apart have a ...
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1answer
2k views

Is it possible to replace a DIAC circuit with an SCR circuit to drive a TRIAC

I have a triac DIAC cirtcuit. I don't have any DIACs on hand, but I do have plenty of TN1215s. Is it possible to generate the required pulses using an SCR to drive the TRIAC's gate?
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2answers
5k views

Phase control up to 40A with TRIAC and DIAC (Optocoupler)

I'm projecting a phase control to control the power given to a resistive load of 6 Ohms using a PLC, TRIAC (BTA40-400), DIAC (Optocoupler MOC3023) and a zero crossing detector (4N25). I've simulated ...
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1answer
256 views

Why isn't the switches being bypassed in this triac/diac circuit?

Just when you think you understand circuits, there's always a curve ball to derail you and leave you scratching your head. The diagram below is a Triac/Diac speed controller for a reciprocating saw. ...
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3answers
7k 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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1answer
875 views

A question about very simple light Dimmer circuit?

I've learned that a Triac works as a switch for controlling AC current. Why not connecting the load (L1) and Triac in series? at the position of red arrow? My reason is that a small amount of current ...