Patent ID: 7602195

Claim:
An electrical circuit, at least partially on a printed circuit board, for determining a design revision status of the printed circuit board, comprising: a node of the electrical circuit on the printed circuit board, to provide an electrical signal; a resistor device of the electrical circuit on the printed circuit board, to receive at least a portion of the electrical signal; an external capacitor device having a capacitance value that is unique to each board revision, connected electrically in series with the resistor device, with respect to the electrical signal, to receive at least a portion of the electrical signal; a counter device to determine a time for the capacitor device to reach a predetermined charge and to assign a value to the time for the capacitor device to reach the predetermined charge; and a system to read the value assigned by the counter device and identify the capacitor from a predetermined list of capacitors, and wherein the identification of the capacitor identifies the design revision status of the printed circuit board.