The performance value table lists the AC Resistance (ACR) and figure of merit (ZT_C) when the cold side ceramic is at Tc. If the thermoelectric module’s ACR is in the range in the table, this usually indicates that the module or generator is in good working order. Measuring of the Direct Current Resistance (DCR) cannot be used to determine health since this would activate the cooling/heating effect of the thermoelectric module. ZT_C is the ability of a material to efficiently produce thermoelectric power. Both ACR and ZT_C are a function of temperature.