Patent ID: 7173445

Claim:
A sensor for inspecting a conductive pattern of a circuit board, comprising: a plurality of sensor elements for detecting in a non-contact manner potential variation which is generated in said conductive pattern in response to an inspection signal supplied to said conductive pattern, each of said sensor elements including: a passive element composed of a metal electrode which is formed on a semiconductor single-crystal to serve as a counter electrode for achieving a capacitive coupling with said conductive pattern to detect the potential variation in said conductive pattern, and a transistor operable, in response to a selection signal, to output a detection signal generated in said passive elements, wherein said transistor is first and second MOSFETs which are connected in series with each other, wherein said first MOSFET has a gate connected with said passive element, and a source whose potential is varied according to a potential of said passive element applied to said gate, and said second MOSFET has a gate connected with said selection signal, wherein said second MOSFET is operable, in response to said selection signal, to receive the potential of said source of said first MOSFET by its drain, and output said received potential from its source as said detection signal.