A circuit capable of selectively operating in an inspecting mode or a driving mode for a display is formed in an integrated circuit and on a glass substrate. The circuit in the IC has a control circuit, a first input circuit, a second input circuit and a fourth input circuit. Each input circuit has a switch. Two additional switches are respectively connected between the first and the second input circuits, and between the second and the fourth input circuits. The glass substrate forms multiple connecting terminals corresponding to the input circuits. Two connecting terminals on the glass substrate are shorted. The control circuit outputs a signal to control all switches to form a configuration suitable for inspecting mode. When inspecting processes are completed, the control circuit changes the configuration for driving mode. The junction resistance of the display is precisely measured and areas in the IC are effectively used.