Potential sensor for detecting voltage of inspection target at non-contact condition to attain higher speed of inspection
AssigneeMitsubishi Heavy Industries, Ltd.
InventorsShinichi Murakawa, Soumyo Doi, Yoshio Egashira, Tadashi Rokkaku, Shigeo Ueda
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Abstract
A potential sensor, includes a field effect transistor, a power supply and a switching device. The power supply supplies a direct current voltage to a gate electrode of the field effect transistor. The switching device switches between connecting the gate electrode to the power supply and disconnecting the gate electrode from the power supply. When the gate electrode is connected to the power supply, the field effect transistor is in action. When the gate electrode is disconnected from the power supply, the field effect transistor is in action.
Claims20
A potential sensor, comprising:
- a field effect transistor;
- a power supply supplying a direct current voltage to a gate electrode of said field effect transistor;
- and
- a switching device switching between connecting said gate electrode to said power supply and disconnecting said gate electrode from said power supply, and
- wherein when said gate electrode is connected to said power supply, said field effect transistor is in action, and when said gate electrode is disconnected from said power supply, said field effect transistor is .in action.
A potential sensing method, comprising:
- (a) providing a field effect transistor;
- (b) providing a power supply supplying a direct current voltage to a gate electrode of said field effect transistor;
- (c) providing a switching device switching between connecting said gate electrode to said power supply and disconnecting said gate electrode from said power supply;
- (d) applying a voltage to an inspection target;
- (e) coupling said gate electrode through an air-gap to said inspection target;
- (f) connecting said gate electrode to said power supply;
- (g) disconnecting said gate electrode from said power supply after said (f);
- and
- (h) outputting said voltage applied to said inspection target from a source electrode of said field effect transistor while said (g) is performed.
Dependencies are inferred from the claim text.