EXTERNAL FORCE DETECTION APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide an external force detection apparatus capable of highly accurately and stably detecting external force applied to a piezoelectric piece.SOLUTION: In an apparatus in which when a quartz piece 2 is bent in accordance with external force, variable capacity of an oscillation loop of an oscillation circuit 5 is changed and the external force is detected by grasping the change of the variable capacity as a change of an oscillation frequency, a variable capacitor diode VD capable of adjusting reactance is arranged on the load side of the oscillation circuit 5. The apparatus is loaded with a function capable of adjusting load reactance in a state where external force is forcedly applied to the quartz piece 2 by a vibration motor 8 though a load reactance range of the oscillation circuit increasing detection sensitivity is narrow. Thus, the load reactance can be set to a value capable of obtaining large detection sensitivity by applying external force to the quartz piece 2 and sweeping the load reactance.