25 Apr
2011
25 Apr
'11
1:26 p.m.
One of the easiest things to sue for this are low voltage filament lamps
12V
car bulbs (say a 12V 5W taillight bulb) is fine for a
12V supply. And
probalby
fine for a 15V supply too (yes, the bulb will have a
short life at the
higher
voltage, but not so short as to worry you). For the 5V
line, a 6V bulb is
the
best thing to use, many older cars had 6V electrics
nad you may well be
able
to get a 6V 30W bulb (which will draw around 5A) from
a vintage car parts
company. I bought a couple of headlight bulbs (each with a apr of 30W or
so
filaments and a couple of stop/taillight bulbs (5W and
21W filamnets).
That
gives me a good selection of laod currents (and yes, I
once parallel to
two
filaments of a headleam bubl to give a load drawing
somewhat more than
10A to test a large SMPSU).
Tony, very helpful advice, as always.
On a purely practical note what do you do about connecting the bulbs to the
connectors? I'll need to find a suitable bulb holder, guessing somewhere
like Maplin or RS would have something, although a quick search at Maplin
didn't show anything that looked suitable. But what do you do for the end
that you connect to the power connector? I am sure that with all the
different types of connectors you encounter it might be difficult to come up
with a reliable connection to the connector that will work with all or most
connectors, do you do something custom for each PSU you test or do you have
a more generic solution?
Thanks
Rob