A DIAC is a diode that conducts only after its breakover voltage has been reached momentarily. (From: Wikipedia)
A DIAC's behavior is similar to the voltage breakdown of a triac, but without a gate terminal.
Questions tagged [diac]
37 questions
4
votes
7 answers
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 source is a tie-in inverter. The problem is is…
Paul
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3
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1 answer
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 fully discharged every time VS passes through…
ohmmy
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3
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1 answer
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 most suitable and what are the reasons for that?
user_fs10
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2
votes
0 answers
Analog Timing Circuit with DIAC
I am currently trying to come up with an analog timing circuit to use within a solar tracker. I know using a 555 timer would be relatively easy to do here but I wanted to see if I could come up with a different way to do this. I'm new to designing…
pointy
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2 answers
How do DIACs work?
I edited my whole post for more refreshed information I learned about DIACs.
Let's consider the following circuit and how it works:
First of all the Vs must be higher than break voltage of DIAC so that the DIAC can conduct when the capacitor…
R1S8K
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2
votes
2 answers
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 because of capacitive reactance in circuit (Ce of…
deel
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vote
1 answer
Controlling minimum voltage output with a DIAC/TRIAC dimmer circuit
I purchased a hot plate/magnetic stirrer from Amazon (Model SH-2, a very common cheap device from what I've found) and would like to alter the circuit so that the minimum temperature from it is lower than what I'm currently getting, which is about…
LarryBud
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vote
1 answer
Can I use a TRIAC as an AC switch and an LDR as a switch controller to turn on and off a LED bulb?
I want to use a TRIAC as a switch for an AC light bulb and turn on the bulb when it gets dark and turn it off when it gets light using an LDR.
I want to fully cut off the bulb below a certain intensity of light and fully turn it on above that level.…
Divakar Aryal
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1
vote
3 answers
What is the importance of R1 connected in this circuit?
What is the importance of R1 in this circuit? What would happen if I removed R1 and kept VR1?
Mahmoud Youssef
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1
vote
2 answers
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 problem. Anyone help please on resistor values I…
Edd Tut
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1
vote
1 answer
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 DIAC's datasheet page 8, something that I dont…
Christianidis Vasileios
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1 answer
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 got me thinking was: won't the light bulb…
enrico sebastian
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1
vote
0 answers
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 wanted to join them in series so that when ever…
Mahesh Gupta
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1
vote
1 answer
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. With some inspiration from circuit diagrams posted…
Electro_Boomer
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vote
3 answers
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 or negative to positive.
But, I cant explain…
user_fs10
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