A guarded sense impedance for use in a measurement instrument includes a sense impedance adapted to have a spatially distributed electrical potential and at least one guard structure adapted to have the spatially distributed electrical potential. Thereafter, the gaming machine periodically calculates odds for the horse racing game. The angle is substantially greater than 0 but substantially less than 180 while the angle may range from 90 to 180, such that a significantly increased measured air pressure results over that measured when 180 and 90. Dopants of a second conductivity type are implanted into the semiconductor body. When the interconnect is attached, control signals from the measurement instrument are supplied to the sensing circuit and the output of the sensing circuit is supplied to the measurement instrument. The internal power supply generating circuits are connected via respective switches to the common monitor pad, and the internal power supply generating circuits and the monitor pad are selectively connectable using the switches.