Light dimmer not working

[HenrikOlsson]

Hi Norm,
The MOC3043 is a zero crossing triac driver, meaning it will only switch when the AC at ~0V - not that great for phase angle controller. The datasheet for the CX240D5 is a little bit unclear as it says zero crossing (for resistive loads) and random fire (for inductove loads) but it doesn't say if it's two different versions or if it just works in two different ways depending on the type of load connected. Anyway, a light bulb is pretty resistive so.

The MOC3022N shown in the schematic is a random fire opto-triac and should work.

Another thing to look out for is that a triac may need a certain current to actually stay ON. So if you only pulse the gate of the triac the small 7.5W load may not provide enough current to allow the triac to stay on untill next zero-crossing. Not saying this is the case here but something to be aware of.

/Henrik.

[Acetronics2]

+1 ...

the zero crossing opto triacs or SSR's won't do anything good on this one !!!

change for MOC 3023 or " 3023 " root ...

BTW ... did you understand how the dimmer works ???

and do not forget to wish Steve a Happy New Year !!!

Alain

[mister_e]

and the ACDetect routine will need to be changed... burst mode as it is right now... not sure why this version is still hanging around... might have forgot to upload the right version again lol

[Normnet]

I had suspected the zero crossing.

Steve's code is from my archived files (12-23-2004).
Where can I download a more recent version?
The newest post I have found so far is PICDIM Lamp Dimmer for the PIC12C508 - PICREF-4

Thanks for the fast help!
This board rocks.

Norm

[Normnet]

I have an older Triac the L2004L3.

What voltage AC or DC and value should be applied to the gate?
At present I am only looking for a full on or off condition.

Norm

[Charlie]

General information can be found here: http://en.wikipedia.org/wiki/TRIAC
Information specific to your device can be usually found on the manufacturer's website.
Google is your friend.

[Ioannis]

Norm, it seems that this is a sensitive triac.

On page 2 it says that for a trigger pulse of 1.3V and a 100mA current the holding current of the load will be 5mA only.

But as you can see it needs 100mA trigger pulse!

On page 4 on the top diagram, there is a relation of the temperature to the holding current, which fall as the temperature rises.

To seems more appropriate to drive it with a small transformer, so that a 5V pulse will be lowered to 1.3 but with an increase in current drive. A 5V at 20mA will be transformed to a 1.3 at about 70mA.

HTH,
Ioannis

[Normnet]

and the ACDetect routine will need to be changed... burst mode as it is right now... not sure why this version is still hanging around... might have forgot to upload the right version again lol

I now have an optoisolator MOC3021 and a triac Q4010L4 which switch the lamp on and off OK however no dimming.
An LED connected to the PIC output to the optoisolator however does brighten and dim.
What needs to be changed on the ACDetect routine?
I did a site search for a newer version but no luck.


Norm