| 摘要 |
<P>PROBLEM TO BE SOLVED: To measure a forward voltage regardless of the direction of the subject when connected, keeping its current state intact, and without incurring a reduction in life. <P>SOLUTION: In a constant current output unit 4, a voltage V1 which is less than a smallest maximum reverse voltage VRmax among the maximum reverse voltages of each light-emitting diode 11 and which exceeds the maximum value VFmax of the forward voltage VF of each light-emitting diode 11 is defined as a maximum output voltage in absolute value. A processing unit 5 lets the constant current output unit 4 output a constant current I1 in both polarities, and measures the absolute value of a terminal voltage V2 in each polarity as judgment voltages Vj1 and Vj2. When only the judgment voltage Vj2 is equal to the voltage V1 and the judgment voltage Vj1 is less than the voltage V1, the diode 11 is determined to be connected in forward direction, or when only the judgment voltage Vj1 is equal to the voltage V1 and the judgment voltage Vj2 is less than the voltage V1, the diode 11 is determined to be connected in reverse direction. When connected in forward direction, the forward voltage VF is measured with the constant current I1 of positive polarity, or when connected in reverse direction, the forward voltage VF is measured with the constant current I1 of negative polarity. <P>COPYRIGHT: (C)2013,JPO&INPIT |
