I-S
Good Evening.... Infidel
I recently had occasion at work to do some measurements using 0-10ohm trimming pots. I had to balance several of these pots to the same resistance.
However, I was finding that I could not get the pots to read less than around 0.68 ohms (using an agilent 6.5 digit bench dmm). I was also having significant problems in getting consistent readings, as they were fluctating rather.
Long story short, I took apart the test leads and cleaned both the wire-connector contact points and also the connector (4mm) surfaces. I also cleaned the probe contact surfaces. Both were done simply using Isopropyl alcohol and some tissue paper.
The result was that I was now getting consistent readings at 0.127 ohms, without having changed anything else at all.
In the scheme of things for a line level connection this is pretty much insignificant as the input impedance of a line input is usually 20-30k ohms, but on a speaker connection this is absolutely a significant level.
However, I was finding that I could not get the pots to read less than around 0.68 ohms (using an agilent 6.5 digit bench dmm). I was also having significant problems in getting consistent readings, as they were fluctating rather.
Long story short, I took apart the test leads and cleaned both the wire-connector contact points and also the connector (4mm) surfaces. I also cleaned the probe contact surfaces. Both were done simply using Isopropyl alcohol and some tissue paper.
The result was that I was now getting consistent readings at 0.127 ohms, without having changed anything else at all.
In the scheme of things for a line level connection this is pretty much insignificant as the input impedance of a line input is usually 20-30k ohms, but on a speaker connection this is absolutely a significant level.
