Re: Best capacitor for back-up applications
- From: Chris Jones <lugnut808@xxxxxxxxxxxxxxxx>
- Date: Sat, 04 Aug 2007 18:03:04 +0100
Eeyore wrote:
AJ wrote:
"Eeyore" wrote
AJ wrote:
I was just wondering what the best type of capacitor I should use for
a
back-up application (> 5uA). I am looking for something surface mount
around the 100-330uF range with a low profile and as cheap as
possible. Any
suggestions?
A coin cell ?
I would rather use a cap as I only need an hour or so of back-up time.
Well..... 330uF won't do it.
dV/dt = I/C = 5uA/330uF = 15mV/sec
In even 100 seconds, the voltage on the cap will have dropped by 1.5V. So
to get a reasonable voltage drop after an hour, you're probably looking at
~ 33000uF. In other words nothing small.
Use a coin cell.
Or one of those super-capacitors that they put in VCRs for running the clock
during power cuts. You can get them in values between 0.1 Farad and a
couple of Farads. They are usually cylindrical about 20mm or 3/4 inch
diameter and about 12mm high (half inch).
http://www.pollin.de/shop/shop.php?cf=detail.php&pg=OA==&a=NTc0OTg3OTk=&w=Nzk3OTk4&ts=0
Chris
.
- Follow-Ups:
- Re: Best capacitor for back-up applications
- From: Eeyore
- Re: Best capacitor for back-up applications
- References:
- Best capacitor for back-up applications
- From: AJ
- Re: Best capacitor for back-up applications
- From: Eeyore
- Re: Best capacitor for back-up applications
- From: AJ
- Re: Best capacitor for back-up applications
- From: Eeyore
- Best capacitor for back-up applications
- Prev by Date: Find out How to Activate Iphone Hidden Feature
- Next by Date: Re: 7.1 speaker: rear and side speakers on same output channel?
- Previous by thread: Re: Best capacitor for back-up applications
- Next by thread: Re: Best capacitor for back-up applications
- Index(es):
Relevant Pages
|
