DIYbanter - View Single Post

Ralph Mowery

In article ,
says...

On Wed, 29 Jun 2016 17:30:13 -0400, Ralph Mowery
wrote:

In article ,
says...
did not come close to the formular for voltage drop. Some
checking the clips and thought the crimp may be bad. Soldered them and
still not beter. The wire its self had about 1/2 of an ohm in 18
inches.

Wow, that's a lot. I just bought another bag of those jumper wires,
but I still have about 8 from 20 or 30 years ago. I think they're
longer too so I should be able to tell them apart, and I will rely on
the old ones.

I'll go measure the new ones when I'm there and I think of it.

I could not believe it at first. I was using a Fluke 87 meter during
the tests and knew it should be accurate. I finally went to the ohms
scale and cliped the wires between the probes. I could short the probes
with the wires and see about half an ohm difference. Could not hardly
believe it myself, but it would seem to be correct.

I got onto this when I had a resistor that was suspose to be one ohm and
a power supply putting out about an amp in the circuit. The power
supply should have been set at 1 volt to do this,but I had to set it to
2 volts to get the 1 amp. That would have been about right when I had 2
of the jumpers in the circuit with my 1 ohm resistor. Made it a 2 ohm
load instead of 1 ohm.

First I thought it was my meter leads or drop across the meter, but it
wasn't. Just those sorry jumpers. I found some 22 gauge wire and
remade the jumpers and the current and voltage calculated out correct
for the resistance.