How can I extend the ammeter wires to my shunt?
Alex Freeman to the contrary, you should have no problem with the resistance of the extension. An ammeter which uses an external shunt looks something like







simulate this circuit &ndash; Schematic created using CircuitLab

The gain amplifier will normally have a fairly high impedance, so the added resistance of the leads should not be a problem. What you do need to watch out for, though, is noise pickup on your extension. The shunt, extension wire and amplifier make a loop, and any net magnetic fields within the loop will induce currents. Since the impedance of the amplifier is high, even very small currents will produce relatively large voltages. Stray 60 Hz is a common source of unwanted nasties. The solution is to use twisted pair for the extension, and perhaps (if the situation calls for it), shielded twisted pair.