Patent ID: 7973543

Claim:
A measurement apparatus that measures a current flowing through a load, comprising: a power supply section that outputs a current supplied to the load; a current measuring section that measures a load current flowing between the load and the power supply section; a switch that is connected in parallel with the current measuring section between the load and the power supply section; and a control section that disconnects the switch during measurement of the load current and connects the switch when the load current falls outside of a predetermined reference range, wherein the current measuring section includes: a sense resistor that is connected in parallel with the switch between the load and the power supply section; a first potential difference detecting section that detects a potential difference between ends of the sense resistor; and a current detecting section that detects the load current based on the potential difference detected by the first potential difference detecting section, and the control section includes: a second potential difference detecting section that detects a potential difference between ends of the switch; a judging section that judges whether the potential difference detected by the second potential difference detecting section is within a voltage range set according to the reference range; and a control circuit that connects the switch when the judging section judges that the potential difference is outside of the voltage range.