To the power off

Hi guys, does anyone have a ref, link, what componet(s) are in play for 100% controls of 220V. Way back in my time we used optos, some discrete components and then some triac or thyristor. But I think it has been changed for the last 30 years, I’m kind of trying to catch up on the hw side.

Any ideas how it is to be done, this BLE & MCU controlled dimming off …on the power side?

@ PiWi - maybe this helps: microcontroller - Arduino 230v Light bulb dimming - Electrical Engineering Stack Exchange

@ PiWi - I’ve just finished laying out a four-channel zero-crossing opto-isolated board to do this with a Gadgeteer port for PWM on three channel plus digital I/O on the fourth. I’ll drop you my schematic when I get to my other PC later.


What’s the Maximum volage and Ampere it can take?
I would Need something similar for up to 3 water pumps for my house heating Controller project.

@ Reinhard Ostermeier - I’m still finalising the details but 240VAC and the power triac is rated at 8A. It’s this one -

Here’s the render. I still have some testing to do and then manufacture.

I welcome your thoughts.

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@ Jason - I would recommend to move the gadgeteer connector further away from the high voltage parts.

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I agree and whilst some tracking has been completed I’m still not 100% happy with the layout. Main voltage does strange things and is very dangerous. I’m just trying to balance the size v’s cost of the board. Give my max size or the same price is 100mmx100mm it is likely to go larger and therefore the separation (from a safety and EMC perspective) will increase.

@ Jason, super. Already thanks for the schematics!

8 Amps should be more than enough.
But I also would take into design, that the high voltage part Needs to be protected against touching it.
Personally I would split it into two boards, where the high voltage part gets an plasic housing.

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@ Jason - I would make sure that there is sufficient PCB copper surface area for the heat dissipation. NXP has a application note that might help:
One of the examples given uses the BTA208S that you have spec’d. For a 1.4Amp motor load they recommend 500mm^2 copper PCB heat sink. So about 1" x 1" copper pad.

One option, which might be cost prohibitive, is to use pre-packaged solid state relays. The cost is definitely higher but it would also give a little more peace of mind that it was safer.

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@ Reinhard Ostermeier - Nice idea. I’ll take a look at the implications.

@ skeller - Price for these is high. I never really intended to go to the market with this and the 8A max current is way more than I need for a couple of 60W-100W bulbs, but I’ll look at the app note and see what should be improved.

Many thanks.

Most times I am using Sharp SSR :
S202S02 Series, 8A
S202T02 Series, 2A
with or without zero crossing detection

@ Jason - I would also recommend to add the pads and traces near the 230V connectors to add a snubber network (R/C) to each output and also space for a transient suppressor.

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It sounds like you’ve done this before. I appreciate your suggestions. I’m going to work them into this design and see where I get to. I’ll post the updates shortly. Any suggestions for transient suppression?

Transient suppressors are not always needed, mostly for inductive loads. I would add a DO-214 landings pattern close to the connector without populating it. The one who use your board might solder one if there is a need. see:

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How do these modification seem?

TVS and snubber added as per your previous post. The layout doesn’t look too bad with the extra components, some thicker tracking and copper pours for heat sinking. It’s not completed yet and the board size has gone up some but still within the size I’d like.

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@ Jason - C1 needs to be connected to pin 1 of the triac, not pin 3

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