INEXPENSIVE POINTING STICK CIRCUIT

摘要

PROBLEM TO BE SOLVED: To inexpensively and highly precisely execute a processing by generating reference voltage approximated to voltage generated by plural resistors connected as a voltage divider, adding the voltage lamp of a known slope to reference voltage clocking the generation of the matching of reference voltage and the voltage lamp and measuring a ratio with the change of voltage. SOLUTION: Distortion gauges 11-14 fitted to the cantilever of a pointing stick are connected as two parallel semi-bridge circuits. X and Y input signals are generated by the voltage divider constituted of the strain gauges 11 and 12 and the distortion gauges 13 and 14. At that time, a field effect transistor(FET) 15 is closed and the strain gauges 11 and 13 are connected to reference voltage VREG. A Z signal is generated when FET 15 is opened and a sensor is connected to reference voltage VREG through the resistor 16. The voltage lamp of the known slope is added to reference voltage, the matching of reference voltage and the voltage lamp is clocked and the ratio is measured by the change of voltage.