| 主权项 |
1. An impedance detector for detecting an impedance of an element of an oxygen concentration sensor, the impedance detector comprising:
a current application portion applying an impedance detection current for detecting an impedance of the element to the element; a detection portion detecting a difference between a current application prior voltage and a current application subsequent voltage, the current application prior voltage being a voltage between both ends of the element before the element is applied with the impedance detection current, the current application subsequent voltage being a voltage between both of the ends of the element when the element is applied with the impedance detection current; and a calculation portion calculating the impedance of the element based on the difference detected by the detection portion and a value of the impedance detection current applied to the element by the current application portion, wherein the current application portion is configured to change the value of the impedance detection current applied to the element, the impedance detector further comprising a changing portion determining to change the value of the impedance detection current that the current application portion applies to the element according to the difference detected by the detection portion. |
