Patent ID: 6980407

Claim:
An arc fault circuit interrupter comprising a transformer having a primary winding for connection to line current and a weakly coupled secondary winding, a rectifier circuit connected to the secondary winding, the rectifier circuit connected to a translator circuit, said translator circuit having a capacitor whose voltage is proportional to the logarithm of the charge delivered by the rectifier circuit, a microcontroller having inputs and outputs, the capacitor being connected to an input of the microcontroller for measuring said capacitor voltage and to an output for resetting the capacitor voltage, a line voltage detection circuit for generating a signal proportional to line voltage, the line voltage detection circuit connected to an input of the microcontroller to enable the microcontroller to take measurements of the capacitor voltage at selected absolute values of the line voltage, the microcontroller generating an output responsive to the measured capacitor voltage, said output providing an indication of the existence of an arc fault.