Triac with uC design attached

[skmdmasud]

will this part of my circuit work. No isolation.

Thanks and Regards.

 

[Misterbenn]

Its a very small snapshot of your circuit but yes this is possible. I assume your PIC is using the Neutral as ground reference, and the PIC is battery powered?

I found one circuit online similar to this with the full 230Vac across the PIC. If that's what your thinking then you shouldn't be let near electronics .... on the other hand I say go on try it, see what happens and send us a photo afterwards.

 

[ericgibbs]

hi skm,
I would not advise you to try it without seeing the full circuit schematic you are using.
Please post the full circuit.

If the PIC 0V is referenced to Neutral and the Triac Gate is referenced to Line, which it appears to be, do not plug it in.
E

 

[tunedwolf]

I would caution you against connecting this to the mains, your circuit as posted will not work as you expect and may even present a real danger to you

 

[skmdmasud]

Hi
here is my full design.

I was thinking :
1. the zero detection input can be taken from my transformer less power supply.
2. The voltage regulator after the transformer less power supply not much useful (i kind of like VRegulators)
3. that about it lol.

 

[tunedwolf]

At the least, you will need to revisit your power supply, for a start, do not use an electrolytic capacitor as your mains dropper! You will also need a higher input voltage to your regulator, a minimum loading and some capacitance on the output in order for the regulator to be stable. The micro on it's own will likely not draw enough current when idle to keep your regulator happy, so add an LED to indicate power or something. There's no need for 2 fuses either, if only one "pops" your circuit is still live, just an accident waiting to happen. You would be better off using an opto-coupler with inbuilt zero crossing detector to drive your triac and concentrate your efforts on safety, your power supply and your remote controller code

 

[large_ghostman]

i think the point is he dosnt have/cant get a zero cross thats why he has a zero cross detector in the circuit?? could he get away with just a opto with non zero cross? i its a fan then it isnt going to switch much?

 

[tunedwolf]

If he can get his hands on an Atmel Micro, he can just as easily get his hands on an Opto-Coupler with Zero Cross built in
Although he may want to do the zero cross detection himself for the practise, the switching of the Fan, I am assuming here, is actually going to be a speed control, otherwise what's the point of a IR remote switch. If that's all he actually wanted, he may as well just buy one

 

[large_ghostman]

might as well buy one applies to all my projects but i still do them, your probably right about zero cross

 

[skmdmasud]

At the least, you will need to revisit your power supply, for a start, do not use an electrolytic capacitor as your mains dropper! You will also need a higher input voltage to your regulator, a minimum loading and some capacitance on the output in order for the regulator to be stable. The micro on it's own will likely not draw enough current when idle to keep your regulator happy, so add an LED to indicate power or something. There's no need for 2 fuses either, if only one "pops" your circuit is still live, just an accident waiting to happen. You would be better off using an opto-coupler with inbuilt zero crossing detector to drive your triac and concentrate your efforts on safety, your power supply and your remote controller code

Hi..
1. Why not use a electrolytic capacitor i don't want to use a transformer because of size. I want the circuit as small as possible so that i can put it inside the switching box in the wall. I can change the zener to 6V and get a higher V for the regulator.

2. Yes NO need for 2 fuse my mistake there.

3. opto-coupler are available and i have used them before for general switching with uC, but since my circuit is not isolated from the mains so i thought about running the triac directly.

So overall is my design ready to work i know there will always be suggestions and improvements from experts .

 

[tunedwolf]

You wouldn't use an electrolytic capacitor dropper because it is 1. polarised and 2. not rated for mains use. Use a Class X rated, film type, capacitor as your dropper. I suggested adding in the opto-coupler to drive the triac, even though it's a non isolated circuit, to relieve you of the additional coding required to reliably detect the mains zero crossings and ensure your firing your triac properly, you can do without it and write the detection code yourself though, if you wish. I would also be adding a snubber network across the triac to prevent commutation

 

[skmdmasud]

You wouldn't use an electrolytic capacitor dropper because it is 1. polarised and 2. not rated for mains use. Use a Class X rated, film type, capacitor as your dropper. I suggested adding in the opto-coupler to drive the triac, even though it's a non isolated circuit, to relieve you of the additional coding required to reliably detect the mains zero crossings and ensure your firing your triac properly, you can do without it and write the detection code yourself though, if you wish. I would also be adding a snubber network across the triac to prevent commutation

I took the capacitor from a energy saver flourescent lamp circuit which runns on 220VAC, and have some more energy saver circuits where they are using polarized caps, I will try to source a film type cap.

2. The triac already has a snubber 0.01uf 400V across.

3. coding part is fun, and hoping it will work.

 

[ChrisP58]

Read ap note AN1003 from Littlefuse/Teccor. It covers direct connection between a triac and a uController.

One thing though, you need to drive the gate pin with respect to MT1, so your uC reference must connect directly to triac pin MT1.

https://www.littelfuse.com/~/media/...rol_Using_Thyristors_Application_Note.pdf.pdf

And remember to be very careful. Make sure you really understand the impact of it being non isolated. Make sure you fully disconect the circuit from the AC line when you connect your programmer. And make sure user contactable device such as switches are able to provide the necessary separation between user and the High Voltage line.

 

[skmdmasud]

Read ap note AN1003 from Littlefuse/Teccor. It covers direct connection between a triac and a uController.

One thing though, you need to drive the gate pin with respect to MT1, so your uC reference must connect directly to triac pin MT1.

https://www.littelfuse.com/~/media/...rol_Using_Thyristors_Application_Note.pdf.pdf

And remember to be very careful. Make sure you really understand the impact of it being non isolated. Make sure you fully disconect the circuit from the AC line when you connect your programmer. And make sure user contactable device such as switches are able to provide the necessary separation between user and the High Voltage line.

Thanks i was looking for some material like that but didnt find in google.

There will only be one switch in the inside to program the remote buttons. Other than that there is no button its totally IR Remote controlled.
Still need to figure out how to manual turn ON OFF things lol.

Thanks for the advice. As i said I have to be super careful.

Regards.