Resistance measurement and current control

An apparatus comprising:

• a resistive element and a diode arranged in series;
• current control circuitry configured to switch a current supplied to the resistive element and the diode between a first current I1, a second current I2 and a third current I3, where I1>I2>I3;
• and
• measuring circuitry configured to determine a resistance R of the resistive element in dependence on a first voltage V1 across the resistive element and the diode when the first current I1 is supplied, a second voltage V2 across the resistive element and the diode when the second current I2 is supplied, and a third voltage V3 across the resistive element and the diode when the third current I3 is supplied;
• wherein the measuring circuitry is configured to combine the first voltage V1, the second voltage V2 and the third voltage V3 to at least partially eliminate an error in the determined resistance R of the resistive element caused by a voltage drop across the diode;
• wherein the resistive element is one of an array of resistive elements arranged in rows and columns, wherein each resistive element is individually addressable via a corresponding row line and a corresponding column line and is arranged in series with a diode between the corresponding row line and the corresponding column line.