Patent ID: 7403021

Claim:
A testing circuit adapted for an interface, the testing circuit comprising: a load feeding circuit comprising a resistance-regulating unit, a first comparator, a pass element, and a capacitor, the resistance-regulating unit connected to a positive input of the first comparator, a negative input of the first comparator connected to the capacitor and a first terminal of the pass element, an output of the first comparator connected to a second terminal of the pass element, a third terminal of the pass element connected to the interface, a load applied to the interface being regulated by changing a resistance value of the resistance-regulating unit; and a voltage testing circuit comprising a second comparator and a display member connected to an output of the second comparator, a voltage of the interface being input to one input of the second comparator to compare with a reference voltage, the second comparator outputting a signal to control the display member to display a comparison result.