Problem with TRIAC and resistive load

Hi
I used circuit below. it seems simple. it works properly but after some while the BT136 born.
I guess it's lead by dI/dT limitation.
let me know about your ideas? how can I solve the problem?

Hi,

is it 220V AC? (I see "22>V") Please confirm.

--> use the "Typical Application Circuit" like given in the MOC datasheet. There is a good reason why they take the effort to design it and include it to the datasheet.
If you don´t follow the datasheet recommendation, you shouldn´t be surprised about failure.

Without knowing any specifications about the load, we can´t verify load behaviour. Mind that incandescent light bulbs have high inrush current.
What about the temperature of the triac?

For sure there is stray inductance.. all the wiring from power plant to your load...Thus I´d expect some overvoltage peaks. An overvoltage protection may be useful.


Klaus

for a cold bulb the peak current can be very high - can exceed the di/dt for the device at turn on, also if you turn on at mains peak you may exceed the peak gate current wth your simple circuit...

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try reading books about triac applications ....

I drive an AC motor perfectly. 40w and 60w single phase AC motor. I have Snobber and it's complete.
but TRIAC born after several months when I use bulb lamps.

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KlausST said:

is it 220V AC? (I see "22>V") Please confirm.

Click to expand...

voltage is about 220V AC

KlausST said:

--> use the "Typical Application Circuit" like given in the MOC datasheet. There is a good reason why they take the effort to design it and include it to the datasheet.
If you don´t follow the datasheet recommendation, you shouldn´t be surprised about failure.

Click to expand...

I have a problem with BT136, not MOC.
If you have good note let me know about that.
TNX

KlausST said:

Without knowing any specifications about the load, we can´t verify load behaviour. Mind that incandescent light bulbs have high inrush current.
What about the temperature of the triac?

Click to expand...

load it completely resistive[normal 100W bulb lamp]. its temperature is normal, in fact, it's not even warm.

Hi,

I have Snobber

Click to expand...

I can't find a snubber.

I have a problem with BT136, not MOC.

Click to expand...

Let's say you have a LED, rated with 20mA...and a current limiting resistor, wrongly dimensionated to supply the LED with 50mA.
The LED fails.
For sure you can say you have a problem with the LED then, but the resistor is responsible for that..
***

A device mainly fails because of overvoltage, overcurrent, overtemperature...(all short time or long time) thus I questioned these three items.

I see no protection against overvoltage, (caused by stray inductance)
I see no protection against overcurrent (load inrush current, gate current)
I see a driving circuit not according datasheet

It seems you don't want to modify a thing, so what "helping answer" do you expect?
It surely won't help if one says "you made everything right".

Klaus