[chbot] Robotics Group meeting, Monday 19 Nov 2018, 630pm, 5 Idris Road

[Volker Kuhlmann]

On Mon 19 Nov 2018 23:09:26 NZDT +1300, Mark Atherton wrote:

> I have seen that schematic before, however the implementation as an
> Arduino Nano shield looks like a death trap to me.

Yes, agreed, a Very Dumb(TM) idea. But that was only for the link. Click
on schematic and you get the hackaday article with the real dirt. Forget
the shield rubbish.

If the SMD resistors are specd for 250Vac/350Vdc in the datasheet I
don't see a problem, the 2016 (metric) size I think isn't so one would
have to go up in size. I just used TH parts. TE Connectivity LR1F220K.

> Would like to see an opto with at least 1kV AC isolation. Also
> enough PCB room to allow for a decent isolation gap.

Vishay 4N35, 5kVrms ;-)
I think other manufacturers' 4N35 weren't as high. I didn't use a socket
because I wasn't sure of its isolation. The gap is prescribed by the
DIP6 package size, pitch is 7.62mm so you get about 6mm from the edges
of the copper, comfortably more than the 4mm required.

> http://www.magazines007.com/pdf/High-Voltage-PCDesign.pdf seems to
> be quite interesting and relevant.

Well, I'm not doing 40kV and don't plan to design a PCB for it. FR-4 is
accepted material for 240Vac.

Thanks,

Volker

-- 
Volker Kuhlmann
http://volker.top.geek.nz/	Please do not CC list postings to me.