Just had a look over your circuitry, and would have the following comments:
There are no decoupling capacitors on the VCC or +12V rails. I would
100nF caps on the VCC pins of all the ICs, and possibly a 10uF overall on
would recommend at least a 10nF and some sort of electrolytic on the HV PSU
connector, Also a 10nF on the power for noise reduction.
For T9, have you considered a N/P pair MOSFET? You could remove R24 if you
did that. I often use a device which has a N and P FET in one package.
I assume I2C has pull-ups on the Micro? Also, if noise is an issue you
a 22pF (or around that value) capacitor on each of those lines.
Drawing style wise, there’s a few places where text is overlapping that
with sorting so that it would be easier to read.
The only other issue is that even though there is a “open hardware” sticker
it, there is no statement of license or copyright.On 1 July 2014 11:59, Wes Gaunt firstname.lastname@example.org wrote:
I’ve attached the most recent schematic, the only bit I haven’t tested of
yet is the MOSFET circuit in the bottom left corner. The MOSFET has just
arrived this morning so set it up for testing ASAP. The only other thing to
note is that N1-6 are 133V forward voltage ‘cold-cathode’ display tubes
which require about 2mA for continuous op. As I’m multiplexing I’ve dropped
the anode resistor to 10K (for 1/3 duty cycle) vs 22K which I used for
continuous operation. I’ve tested them with a 500Hz pwm with 1/3 duty cycle
to as low as 6k8 anode resistance without trouble but to be on the safe
side I bumped it back up.
Hope this is fine, and I look forward to meeting you all tomorrow evening.
On Monday, 30 June 2014 21:33:42 UTC+1, Wes Gaunt wrote:
I just recently discovered about hackspaces and would be really
interested about getting involved with one. My name is Wes Gaunt, I’m from
Stockport and I’ve just finished my A-levels.
Is it alright if I come to the open evening on Wednesday to look around
and meet people, I’m currently working on a Nixie tube clock project and am
planning on sending my PCB off to OSH park in a couple of days, so it would
be very helpful if someone could look over my design before hand.
Hope this is alright.
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