Ohmmeter

The standard way to measure resistance in ohms is to supply a constant voltage to the resistance and measure the current through it. That current is of course inversely proportional to the resistance according to Ohm's law, so that you have a non-linear scale. The current registered by the current sensing element is proportional to 1/R, so that a large current implies a small resistance. Modern solid-state meters have digital readouts, but the principles of operation can be better appreciated by examining the older moving coil meters based on galvanometer sensors.