the width of the power trace is calculated based on transient and maximum current carrying capability as such it was important not to minimize the ability of the power circuit itself to carry such maximum currents in view of this a secondary current carrying path 28 was added into the circuit to provide an alternate path for current flow at the point of thermistor placement such an alternate path 28 insures the ability of the overall circuit to carry such high transient currents the provision of an alternate path would also allow the current actually flowing through the defrost heater 14 to take different paths and therefore the temperature rise sensed by thermistor 22 would not be representative of the actual current flowing through the defrost heater 14 to overcome this problem the length and therefore the resistance of the alternate path 28 was made to ensure that under normal operating conditions the majority of the current flowing through the defrost heater 14 will flow through the power trace 26 path as opposed to the alternate path 28 in this way the calculation within the adc controller 12 maintains accuracy indeed in one embodiment of the present invention the current ratio flow between paths 26 and 28 may also be taken into account with the.