14 Jul
2012
14 Jul
'12
2 p.m.
On Sat, 14 Jul 2012, Tony Duell wrote:
Maybe in large volume it resulted in a cost savings with a very tiny cost
savings per unit for them to use a capacitor with slightly less aluminum
in it?
I'm
getting around to doing some work on my veneered and generated
HP5307A frequency counter. Looking at all the gold-plated PCB goodness
inside, the first thing that jumps out at me is a bulging electrolytic.
It's a 940 uF, 40V unit. Not 1000 uF, but 940. Not 50V, but 40V. I'm
going to substitute a pair of 470uF, 50V units paralleled as a
substitute, but this had me wondering if anyone knows why the strange
values, particularly since +/-20 percent tolerances are common on
electrolytic caps.
I'e wondersd about this before (I may even have posted about it). I
can;'t see any electrical rason why they would use such capacitors. I've
seen a PSU board where the smoothing capacitors for the inputs to
various regulators were a mix of (I think( 5600uF and 6000uF, again
+/-20% (at least). Why theey didn't specify and ft al lthe same type is
beyond me.