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Date:	Wed, 10 May 2023 13:10:55 +0200
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Subject:	[geda-user] [off-topic] Large resistance value SMD resistors?
To:	geda-user AT delorie DOT com
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	<6104f4a8-ad58-82a0-03eb-4e6c8da2ca82 AT k4gvo DOT com>
From:	"Richard Rasker (rasker AT linetec DOT nl) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
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Hi all,

My apologies for this off-topic question, but I'm running into a 
question for which I can't find a good answer online -- and I know that 
some people here have special expertise

I'm asked to evaluate another tech's design, and apart from the 
inevitable small optimization things, he did a fine job. There is 
however one thing I'm not sure about: the circuit features a couple of 
22 megohm resistors, and the current choice is simply a 0603 size. As 
the device in question may be used in environments without proper 
climate control, I think that moisture (condensation) may on occasion 
become a problem given the short insulation distance. All voltages are 
15 volts and lower, so there's no hazard involved, but the circuit's 
specifications are no longer met if the resistance drops below ~15 megohms.

Would it be better to use a larger resistor (e.g. 1206), or forego SMD 
altogether? I can of course also specify a moisture-resistant PCB 
coating, but that is a rather expensive extra production step.

Thanks in advance for any ideas,

Richard Rasker

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