In the chart above, as voltage applied to a typical resistor is increased, the current increases linearly though the resistor.  If the current (and therefore the resulting power dissipation) increases beyond the resistor’s rated value, electrical break down may occur. Current though the POSISTOR® also increases linearly when it is operating under normal conditions. When current through the POSISTOR® exceeds the specified Protective Current, the POSISTOR®’s resistance rapidly increases, and thereby limits the current. The POSISTOR® has a constant-resistance characteristic up to its Protective Current. Above this point, it has a constant-power characteristic, which protects the circuit.