19 Jul
2000
19 Jul
'00
1:03 a.m.
On Wed, 19 Jul 2000, Mike Ford wrote:
Yes. The simpson is an excellent meter but it is a VOM and it places a
load on the circuit under test of 20,000*(volts scale in use). Some
circuits don't like this and a fet VM presents a high resistance load
(11megohms typical). It's worth having, especially if they are cheap.
Allison
Incidentally,
an analogue multimeter can be more use than a digital one
for some work. It's a lot better at showing trends, indicating when the
amplitude of a signal is peaking, etc. Accuracy is not that important in
most repairs -- certainly +/-5% is easily good enough for most work.
I still have my big Simpson VTVM, but one of the surplus joints in town has
a bunch (dozens) of HP (I think) FET versions, the ones that used to be so
common in labs about 8" tall, 5" wide, and maybe 5" deep with a nice wide
mirror scale etc. Any sane reason I should get a few of them?