<html><head/><body><html><head><meta content="never" name="referrer" /><meta content="no-referrer" name="referrer" /><meta name="viewport" content="width=device-width" /><meta http-equiv="Content-Type" content="text/vnd.ui.secure+html;charset=utf-8" /></head><body style="overflow-wrap:break-word; word-break: break-word;"><div class="mail_android_message" style="line-height: 1; padding: 0.5em">Just to chime in, I agree with cheater00's assessment, and Mattias' research.<br>
<br>
When I worked for a company that made high quantity PCIe to SAS host bus adapter boards, before the prototypes were built a component derating review was done to make sure none of the components were used too close to their nominal ratings for current and voltage. This was mostly to ensure the assembly's MTBF was over 1,000,000 hours, for reliability.<br>
<br>
We mostly used ceramic caps for switching regulator and supply rail bypass circuits.<br>
<br>
I wouldn't recommend ceramic caps for any circuit where the actual capacitance is critical (filters, oscillators) unless you know the capacitance isn't going to be changing near your operating point.<br>
<br>
Film caps (polycarbonate RIP, long live polypropylene!) for audio.<br>
<br>
Justin <br>
<br>
</div><div class="mail_android_quote" style="line-height: 1; padding: 0.3em">On 04/05/2017, 1:11 PM Mattias Rickardsson <mr@analogue.org> wrote:<blockquote class="gmail_quote" style="margin: 0.8ex 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
On 5 April 2017 at 19:39, Gordonjcp <gordonjcp@gjcp.net> wrote:<br />
><br />
> All very well in theory, but capacitors simply do not behave like that in real life.<br />
<br />
Are you sure?<br />
<br />
<a href="http://www.edn.com/design/analog/4402049/2/Temperature-and-voltage-variation-of-ceramic-capacitors--or-why-your-4-7--F-capacitor-becomes-a-0-33--F-capacitor" target="_blank">http://www.edn.com/design/analog/4402049/2/Temperature-and-voltage-variation-of-ceramic-capacitors--or-why-your-4-7--F-capacitor-becomes-a-0-33--F-capacitor</a><br />
<br />
On 5 April 2017 at 20:03, Tom Wiltshire <tom@electricdruid.net> wrote:<br />
> It looks to me there's something we're not understanding (or<br />
> misunderstanding) here. There's no way a capacitor that is spec'd to 35V<br />
> loses 90% of its capacitance by 35V. That simply wouldn't be *useful*.<br />
<br />
Yes, they are still useful for many applications - if you know the<br />
voltage dependency and your DC voltage, and and choose your capacitors<br />
accordingly. :-)<br />
<br />
/mr<br />
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