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Dimming Halogen Lamp PWM

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lavricalex

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Hy to all,

I want to design a dimming circuit for a 300W Halogen lamp that is controled by a PWM signal from a microcontroler (jn5148).
I use a simple circuit using a triac BTA16 and a optocoupler.
The PWm signal enters the optocoupler and commands the BTA 16.

In this configuration I succeded in making dimming but thete is a problem.

After a regular period of time the lamp goes full power (100%) and then dimms to 50% and the cycle repeats again.

I am running out of options.

Waiting for a replay.

Best regards.
Alex

pic.gif
 

PWM with an obviously free running pulse frequency isn't a resonable option for AC voltage control with a triac switch. You need to perform phase angle control, synchronized to AC supply voltage zero crossing. That's due to the fact, that a triac can't be switched off at will, after triggering it stays on until the next zero crossing.
 
and after you make a good zero crossing signal sync, you MUST place the moc30xx between A2 and G of the triac
(ant NOT between A1 and G like in the schematic you give)

regards,
 
thank s KRIPTON you are right. I redesigned my circuit now I use a simple tranzistor.

Bes regards.
 

lavricalex said:
thank s KRIPTON you are right. I redesigned my circuit now I use a simple tranzistor.

Bes regards.
Click to expand...

hi, I'm searching for AC lamp dimmer circuit too. Can you help me with the schematic? Just the circuit from microcontroller up to the lamp. I really need it.
 

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