JP2016206098A

JP2016206098A - Resistance value measurement method and program

Info

Publication number: JP2016206098A
Application number: JP2015090309A
Authority: JP
Inventors: 純一杉田; Junichi Sugita
Original assignee: Sanken Electric Co Ltd
Current assignee: Sanken Electric Co Ltd
Priority date: 2015-04-27
Filing date: 2015-04-27
Publication date: 2016-12-08

Abstract

PROBLEM TO BE SOLVED: To provide a resistance value measurement method capable of obtaining an accurate resistance value from information of two terminals in which a diode and a resistor are connected in series.SOLUTION: A resistance value measurement method includes: a first measurement step of measuring a voltage between both ends of a series circuit as a first voltage value Vby making a forward current of a first current value Iflow into a series circuit connected with a diode Di and a resistor R; a second measurement step of measuring the voltage between both ends of the series circuit as a second voltage value Vby making a forward current of a second current value Iof n times of the first current value Iflow into the series circuit; a third measuring step of measuring the voltage between both ends of the series circuit as a third voltage value Vby making a forward current of a third current value Iof n times of the second current value Iflow into the series circuit; and a resistance value calculation step of calculating (ΔV-ΔV)/(ΔI-ΔI) as a resistance value Rof the resistance R when ΔV=V-V, ΔV=V-V, ΔI=I-I, ΔI=I-I.SELECTED DRAWING: Figure 1

Description

本発明は、ダイオードと直列に接続された抵抗の抵抗値を測定する抵抗値測定方法、及びプログラムに関する。 The present invention relates to a resistance value measuring method and a program for measuring a resistance value of a resistor connected in series with a diode.

ダイオードと抵抗とを直列接続した直列回路は、例えば、高圧モータードライバ（以下、ＩＰＭと称す）でブートダイオードとして採用されている。このブートダイオードは、２つの端子間にダイオードとブート抵抗とが直列に接続されたブートダイオードチップとしてＩＰＭに組み込まれ、２つの端子がＩＰＭの製品ピンと接続される。ブート抵抗は、ブートチャージ電流を制限し、起動時の意図しないＯＣＰ保護動作を防止する働きがある重要な回路部品である。従って、ブート抵抗値Ｒは、製品仕様書にも記載する情報で、ＩＰＭの製品検査において、２つの端子の情報から測定している（例えば、特許文献１、２、３参照）。 A series circuit in which a diode and a resistor are connected in series is employed as a boot diode in, for example, a high voltage motor driver (hereinafter referred to as IPM). This boot diode is incorporated in the IPM as a boot diode chip in which a diode and a boot resistor are connected in series between two terminals, and the two terminals are connected to a product pin of the IPM. The boot resistor is an important circuit component that functions to limit the boot charge current and prevent an unintended OCP protection operation at the time of startup. Therefore, the boot resistance value R is information described in the product specification, and is measured from information on two terminals in the IPM product inspection (see, for example, Patent Documents 1, 2, and 3).

特許第４７９４８９６号公報Japanese Patent No. 4794896 特許第４２４５０５３号公報Japanese Patent No. 4245053 特許第４４４３６８１号公報Japanese Patent No. 4443681

しかしながら、特許文献１では、抵抗値の算出にボルツマン定数ｋと定数である電荷ｑと用いているため、誤差なく算出することができない。すなわち、ボルツマン定数ｋ及び電荷ｑの何桁目までを計算に入れるかで誤差は変化する。さらに、特許文献１では、抵抗値の算出に絶対温度Ｔを用いているため、被測定回路の温度を測定する必要がある。また、被測定回路の温度測定が困難な場合は、被測定回路の温度をヒーター等で一定になるように管理する必要がある。
特許文献２では、抵抗値を測定できるとされているが、詳細な測定方法について言及されていない。
特許文献３では、２つのダイオードが必要となり、この２つのダイオードが全く同じ特性を有するという仮定に基づいている。従って、ダイオードの製品誤差によって算出される抵抗値にも誤差が生じてしまう。 However, in Patent Document 1, since the Boltzmann constant k and the constant charge q are used to calculate the resistance value, it cannot be calculated without error. That is, the error varies depending on the number of digits of the Boltzmann constant k and the charge q. Furthermore, in Patent Document 1, since the absolute temperature T is used to calculate the resistance value, it is necessary to measure the temperature of the circuit under measurement. Further, when it is difficult to measure the temperature of the circuit under measurement, it is necessary to manage the temperature of the circuit under measurement so as to be constant with a heater or the like.
In Patent Document 2, it is supposed that the resistance value can be measured, but a detailed measurement method is not mentioned.
Patent Document 3 is based on the assumption that two diodes are required and these two diodes have exactly the same characteristics. Therefore, an error also occurs in the resistance value calculated by the product error of the diode.

本発明の目的は、上記の課題に鑑み、ダイオードと抵抗とが直列接続された２つの端子の情報から正確な抵抗値を求めることができる抵抗値測定方法、及びプログラムを提供することにある。 In view of the above problems, an object of the present invention is to provide a resistance value measuring method and a program capable of obtaining an accurate resistance value from information of two terminals in which a diode and a resistor are connected in series.

本発明に係る抵抗値測定方法は、上記の目的を達成するため、次のように構成される。
本発明の抵抗値測定方法は、ダイオードと抵抗とが接続された直列回路に第１の電流値Ｉ_１の順方向電流を流して、前記直列回路の両端間の電圧を第１の電圧値Ｖ_１として測定する第１の測定工程と、前記直列回路に前記第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２の順方向電流を流して、前記直列回路の両端間の電圧を第２の電圧値Ｖ_２として測定する第２の測定工程と、前記直列回路に前記第２の電流値Ｉ_２をｎ倍した第３の電流値Ｉ_３の順方向電流を流して、前記直列回路の両端間の電圧を第３の電圧値Ｖ_３として測定する第３の測定工程と、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_３＝Ｖ_３−Ｖ_２、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_３＝Ｉ_３−Ｉ_２とし、（ΔＶ_３−ΔＶ_２）／（ΔＩ_３−ΔＩ_２）を前記直列回路における前記抵抗の抵抗値として算出する抵抗値算出工程と、前記抵抗値算出工程の算出結果を出力する抵抗値出力工程とを具備することを特徴とする。
また、本発明に係る抵抗値測定方法は、ダイオードと抵抗とが接続された直列回路に第１の電流値Ｉ_１の順方向電流を流して、前記直列回路の両端間の電圧を第１の電圧値Ｖ_１として測定する第１の測定工程と、前記直列回路に前記第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２の順方向電流を流して、前記直列回路の両端間の電圧を第２の電圧値Ｖ_２として測定する第２の測定工程と、前記直列回路に第３の電流値Ｉ_３の順方向電流を流して、前記直列回路の両端間の電圧を第３の電圧値Ｖ_３として測定する第３の測定工程と、前記直列回路に前記第３の電流値Ｉ_３をｎ倍した第４の電流値Ｉ_４の順方向電流を流して、前記直列回路の両端間の電圧を第４の電圧値Ｖ_４として測定する第４の測定工程と、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_４＝Ｖ_４−Ｖ_３、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_４＝Ｉ_４−Ｉ_３とし、（ΔＶ_４−ΔＶ_２）／（ΔＩ_４−ΔＩ_２）を前記直列回路における前記抵抗の抵抗値として算出する抵抗値算出工程と、前記抵抗値算出工程の算出結果を出力する抵抗値出力工程とを具備することを特徴とする。
また、本発明に係るプログラムは、ダイオードと抵抗とが接続された直列回路の両端間の情報に基づいて、前記直列回路における抵抗の抵抗値を測定する抵抗値測定方法をコンピュータに実行させるプログラムであって、前記プログラムは、前記コンピュータを、前記直列回路に第１の電流値Ｉ_１、前記第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２、前記第２の電流値Ｉ_２をｎ倍した第３の電流値Ｉ_３の順方向電流をそれぞれ流した際に、電圧計によってそれぞれ測定された前記直列回路の両端間の第１の電圧値Ｖ_１、第２の電圧値Ｖ_２、第３の電圧値Ｖ_３の入力をそれぞれ受け付ける電圧値入力部と、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_３＝Ｖ_３−Ｖ_２、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_３＝Ｉ_３−Ｉ_２とし、（ΔＶ_３−ΔＶ_２）／（ΔＩ_３−ΔＩ_２）を前記直列回路における前記抵抗の抵抗値として算出する抵抗値算出部と、抵抗値算出部による算出結果を出力する出力部と、して動作させることを特徴とする。
また、本発明に係るプログラムは、ダイオードと抵抗とが接続された直列回路の両端間の情報に基づいて、前記直列回路における抵抗の抵抗値を測定する抵抗値測定方法をコンピュータに実行させるプログラムであって、前記プログラムは、前記コンピュータを、前記直列回路に第１の電流値Ｉ_１、前記第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２、第３の電流値Ｉ_３、前記第３の電流値Ｉ_３をｎ倍した第４の電流値Ｉ_４の順方向電流をそれぞれ流した際に、電圧計によってそれぞれ測定された前記直列回路の両端間の第１の電圧値Ｖ_１、第２の電圧値Ｖ_２、第３の電圧値Ｖ_３、第４の電圧値Ｖ_４の入力をそれぞれ受け付ける電圧値入力部と、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_４＝Ｖ_４−Ｖ_３、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_４＝Ｉ_４−Ｉ_３とし、（ΔＶ_４−ΔＶ_２）／（ΔＩ_４−ΔＩ_２）を前記直列回路における前記抵抗の抵抗値として算出する抵抗値算出部と、抵抗値算出部による算出結果を出力する出力部と、して動作させることを特徴とする。 The resistance value measuring method according to the present invention is configured as follows in order to achieve the above object.
In the resistance value measuring method of the present invention, a forward current having a _first current value I1 is passed through a series circuit in which a diode and a resistor are connected, and the voltage across the series circuit is changed to a first voltage value V. _{A first} measurement step of measuring as 1, and a forward current having a _second current value I _{2 obtained} by multiplying the first current value I ₁ by n times through the series circuit, and a voltage across the series circuit. The second voltage value V ₂ , and passing a forward current of a _third current value I ₃ that is n times the _second current value I ₂ through the series circuit, a third step of measuring the voltage across the series circuit as a third voltage value _{_{_{V 3, ΔV 2 = V 2}}} -V 1, ΔV 3 = V 3 -V 2, ΔI 2 = I 2 -I ₁ , ΔI ₃ = I ₃ −I _2, and (ΔV ₃ −ΔV ₂ ) / (ΔI ₃ −ΔI ₂ ) is the resistance in the series circuit. A resistance value calculating step for calculating the resistance value; and a resistance value outputting step for outputting a calculation result of the resistance value calculating step.
In the resistance value measuring method according to the present invention, a forward current having a _first current value I1 is passed through a series circuit in which a diode and a resistor are connected, and the voltage across the series circuit is flowing a first measuring step of measuring a voltage value V _1, a second forward current of the current value I ₂ which the first current value I ₁ multiplied by n in the series circuit, both ends of the series circuit a second measuring step of measuring the voltage between the second voltage value V _2, by flowing a third forward current of the current value I ₃ in the series circuit, the voltage across the series circuit first 3 a third step of measuring a voltage value V ₃ of the said third current value I ₃ in a forward current of the fourth current value I ₄ that is n times in the series circuit, the series circuit a fourth step of measuring the voltage across the fourth voltage value _{V 4} _{_{_{of, ΔV 2 = V 2 -V 1}}} , Δ ₄ = _V ₄ -V _3, and _{_{_{ΔI 2 = I 2 -I 1,}}} ΔI 4 = I 4 -I 3, of the resistor in the series circuit _{_{(ΔV 4 -ΔV 2) / (}} ΔI 4 -ΔI 2) A resistance value calculating step for calculating the resistance value; and a resistance value outputting step for outputting a calculation result of the resistance value calculating step.
The program according to the present invention is a program for causing a computer to execute a resistance value measuring method for measuring a resistance value of a resistor in the series circuit based on information between both ends of the series circuit in which a diode and a resistor are connected. The program causes the computer to have a first current value I ₁ in the series circuit, a second current value I _{2 obtained} by multiplying the first current value I ₁ by n, and the second current value I. The first voltage value V ₁ and the second voltage value across the series circuit respectively measured by the voltmeter when a forward current having a _third current value I ₃ multiplied by ₂ is passed. A voltage value input unit that receives inputs of V ₂ and the third voltage value V ₃ , and ΔV ₂ = V ₂ −V ₁ , ΔV ₃ = V ₃ −V ₂ , ΔI ₂ = I ₂ −I ₁ , ΔI ₃ = and _{_{_{I 3 -I 2, (ΔV 3}}} -ΔV 2 / A (ΔI ₃ -ΔI ₂₎ resistance value calculation unit that calculates as a resistance value of the resistor in the series circuit, and an output unit for outputting a calculation result by the resistance value calculation unit, characterized in that to operate .
The program according to the present invention is a program for causing a computer to execute a resistance value measuring method for measuring a resistance value of a resistor in the series circuit based on information between both ends of the series circuit in which a diode and a resistor are connected. In the program, the computer is connected to the series circuit with a first current value I ₁ , a second current value I _{2 obtained} by multiplying the first current value I ₁ by n, and a third current value I _3. the third current value I ₃ n times the fourth current value I ₄ of the forward current which was obtained by applying each of the first voltage value between both ends of the series circuit are respectively measured by the voltmeter A voltage value input unit that receives inputs of V ₁ , second voltage value V ₂ , third voltage value V ₃ , and fourth voltage value V ₄ , and ΔV ₂ = V ₂ −V ₁ , ΔV ₄ = V ₄ −V ₃ , ΔI ₂ = I ₂ −I ₁ , ΔI ₄ = I ₄ −I ₃ , (ΔV ₄ −ΔV ₂ ) / (ΔI ₄ −ΔI ₂ ) is calculated as a resistance value of the resistor in the series circuit, and the calculation result by the resistance value calculation unit is It is characterized by operating as an output unit for outputting.

本発明によれば、ダイオードと抵抗とが直列接続された２つの端子の情報から、誤差の原因となる定数項目をキャンセルし、正確な抵抗値を求めることができるという効果を奏する。 According to the present invention, there is an effect that an accurate resistance value can be obtained by canceling a constant item causing an error from information of two terminals in which a diode and a resistor are connected in series.

本発明に係る抵抗値測定方法の実施の形態を行う抵抗値測定装置の構成を示す図である。It is a figure which shows the structure of the resistance value measuring apparatus which performs embodiment of the resistance value measuring method which concerns on this invention. 図１に示す端子間の電圧と順方向電流との関係を示すグラフである。It is a graph which shows the relationship between the voltage between terminals shown in FIG. 1, and a forward current. 本発明に係る抵抗値測定方法の実施の形態によるシミュレーション結果を示す図である。It is a figure which shows the simulation result by embodiment of the resistance value measuring method which concerns on this invention.

次に、本発明の実施の形態を、図面を参照して具体的に説明する。 Next, embodiments of the present invention will be specifically described with reference to the drawings.

本実施の形態の抵抗値測定方法は、図１を参照すると、端子Ｔ１と端子Ｔ２との間に直列接続されたダイオードＤｉと抵抗Ｒとからなる直列回路において、端子Ｔ１と端子Ｔ２との情報から抵抗Ｒの抵抗値Ｒ_ｍを測定する方法である。なお、ダイオードＤｉは、端子Ｔ１から端子Ｔ２に向けて順方向に接続されている。本実施の形態の抵抗値測定方法は、図１に示す抵抗値測定装置１０を用いて行うことができる。抵抗値測定装置１０は、設定された電流値Ｉの順方向電流を端子Ｔ１から端子Ｔ２に向けて流す可変電流源１と、端子Ｔ１と端子Ｔ２との間の電圧Ｖを測定する電圧計２と、抵抗値算出装置３とを備えている。 With reference to FIG. 1, the resistance value measuring method of the present embodiment is a series circuit including a diode Di and a resistor R connected in series between the terminal T1 and the terminal T2, and information on the terminal T1 and the terminal T2. a method of measuring the resistance value R _m of the resistor R from. The diode Di is connected in the forward direction from the terminal T1 to the terminal T2. The resistance value measuring method of the present embodiment can be performed using the resistance value measuring apparatus 10 shown in FIG. The resistance value measuring apparatus 10 includes a variable current source 1 that sends a forward current having a set current value I from a terminal T1 toward a terminal T2, and a voltmeter 2 that measures a voltage V between the terminal T1 and the terminal T2. And a resistance value calculating device 3.

抵抗値算出装置３は、プログラムによって動作するコンピュータ等の情報処理装置であり、操作部３１と、電流値設定部３２と、電圧値入力部３３と、抵抗値算出部３４と、出力部３５とを備えている。 The resistance value calculation device 3 is an information processing device such as a computer that operates according to a program, and includes an operation unit 31, a current value setting unit 32, a voltage value input unit 33, a resistance value calculation unit 34, and an output unit 35. It has.

操作部３１は、キーボード等のユーザーによる入力を受け付ける入力手段であり、可変電流源１に設定する第１の電流値Ｉ_１を受け付ける。また、出力部３５は、ディスプレイやプリンタ等のユーザーに向けて情報を出力する出力手段である。 The operation unit 31 is an input unit that receives an input from a user such as a keyboard, and receives a first current value I ₁ set in the variable current source 1. The output unit 35 is an output unit that outputs information to a user such as a display or a printer.

電流値設定部３２と、電圧値入力部３３と、抵抗値算出部３４とは、抵抗値算出装置３が備えるハードウェア（例えば、ＨＤＤ、ＣＰＵ、ＲＯＭ、ＲＡＭ等）により実現される。具体的には、ＣＰＵが、ＨＤＤもしくはＲＯＭに記憶されている制御プログラムを読み出し、制御プログラムをＲＡＭに展開して実行することで実現される。 The current value setting unit 32, the voltage value input unit 33, and the resistance value calculation unit 34 are realized by hardware (for example, HDD, CPU, ROM, RAM, etc.) provided in the resistance value calculation device 3. Specifically, it is realized by the CPU reading the control program stored in the HDD or ROM, developing the control program in the RAM, and executing it.

電流値設定部３２は、操作部３１によって受け付けた第１の電流値Ｉ_１を可変電流源１に設定する。そして、第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２（Ｉ_２＝ｎ×Ｉ_１）を算出して、第２の電流値Ｉ_２を可変電流源１に設定すると共に、第２の電流値Ｉ_２をｎ倍した第３の電流値Ｉ_３（Ｉ_３＝ｎ×Ｉ_２）を算出して、第３の電流値Ｉ_３を可変電流源１に設定する。なお、ｎは、予め設定された値であっても良く、操作部３１からの入力によってユーザーが設定可能にしても良い。なお、第２の電流値Ｉ_２及び第３の電流値Ｉ_３も操作部３１によって受け付けるようにしても良い。また、第２の電流値Ｉ_２もしくは第３の電流値Ｉ_３を操作部３１によって受け付け、他の電流値に算出して可変電流源１に設定するようにしても良い。 The current value setting unit 32 sets the first current value I ₁ received by the operation unit 31 in the variable current source 1. Then, a second current value I ₂ (I ₂ = n × I ₁ ) obtained by multiplying the first current value I ₁ by n is calculated, and the second current value I ₂ is set in the variable current source 1. Then, a third current value I ₃ (I ₃ = n × I ₂ ) obtained by multiplying the second current value I ₂ by n is calculated, and the third current value I ₃ is set in the variable current source 1. Note that n may be a preset value or may be set by the user by an input from the operation unit 31. Note that the second current value I ₂ and the third current value I ₃ may also be received by the operation unit 31. Alternatively, the second current value I ₂ or the third current value I ₃ may be received by the operation unit 31, calculated as another current value, and set in the variable current source 1.

電圧値入力部３３は、可変電流源１によって第１の電流値Ｉ_１の順方向電流を端子Ｔ１から端子Ｔ２に向けて流した際に、電圧計２によって測定された端子Ｔ１と端子Ｔ２との間の電圧Ｖを第１の測定工程による第１の電圧値Ｖ_１として入力を受け付ける。また、電圧値入力部３３は、可変電流源１によって第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２の順方向電流を端子Ｔ１から端子Ｔ２に向けて流した際に、電圧計２によって測定された端子Ｔ１と端子Ｔ２との間の電圧Ｖを第２の測定工程による第２の電圧値Ｖ_２として入力を受け付ける。さらに、電圧値入力部３３は、可変電流源１によって第２の電流値Ｉ_２をｎ倍した第３の電流値Ｉ_３の順方向電流を端子Ｔ１から端子Ｔ２に向けて流した際に、電圧計２によって測定された端子Ｔ１と端子Ｔ２との間の電圧Ｖを第３の測定工程による第３の電圧値Ｖ_３として入力を受け付ける。 Voltage value input unit 33, a first forward current of a current value I ₁ by the variable current source 1 when the flow direction from the terminal T1 to the terminal T2, the terminal T1 and the terminal T2 measured by the voltmeter 2 Is received as the first voltage value V _{1 in} the first measurement step. Further, the voltage value input unit 33, a second forward current of the current value I ₂ for the first current value I ₁ by the variable current source 1 and n times when flowed toward the terminal T1 to the terminal T2, The voltage V between the terminal T1 and the terminal T2 measured by the voltmeter _{2 is received} as the second voltage value V2 in the second measurement process. Further, the voltage value input unit 33, a third forward current of the current value I ₃ to the second current value I ₂ multiplied by n by the variable current source 1 when the flow direction from the terminal T1 to the terminal T2, It receives an input voltage V between the terminals T1 and T2 measured by the voltmeter 2 third as a voltage value V ₃ according to the third measurement step.

抵抗値算出部３４は、電流値設定部３２によって可変電流源１に設定された第１の電流値Ｉ_１、第２の電流値Ｉ_２、第３の電流値Ｉ_３と、電圧値入力部３３によって電圧計２から受け付けた第１の電圧値Ｖ_１、第２の電圧値Ｖ_２、第３の電圧値Ｖ_３とを用い、次式〔数１〕を算出することで、抵抗Ｒの抵抗値Ｒ_ｍを求め、算出した抵抗Ｒの抵抗値Ｒ_ｍを出力部３５から出力する。 The resistance value calculation unit 34 includes a first current value I ₁ , a second current value I ₂ , a third current value I ₃ set in the variable current source 1 by the current value setting unit 32, and a voltage value input unit. 33 using the first voltage value V ₁ , the second voltage value V ₂ , and the third voltage value V ₃ received from the voltmeter 2 by calculating the following equation (Equation 1), The resistance value R _m is obtained, and the calculated resistance value R _m of the resistance R is output from the output unit 35.

但し、〔数１〕において、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_３＝Ｖ_３−Ｖ_２、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_３＝Ｉ_３−Ｉ_２である。 However, in [Expression 1], ΔV ₂ = V ₂ −V ₁ , ΔV ₃ = V ₃ −V ₂ , ΔI ₂ = I ₂ −I ₁ , and ΔI ₃ = I ₃ −I ₂ .

次に、本実施の形態の抵抗値測定方法のメカニズムについて詳細に説明する。
図１に示すように、端子Ｔ１から端子Ｔ２に向けて順方向電流Ｉを流すと、端子Ｔ１と端子Ｔ２との間の電圧Ｖは、ダイオードＤｉの端子間の電圧Ｖａと、抵抗Ｒの端子間の電圧Ｖｂとを加算した値となる。ここで、ダイオードＤｉについて次式〔数２〕が成立する。但し、〔数２〕において、Ｉ_ｓは飽和電流、ｑは電荷、ｋはボルツマン定数、Ｔは絶対温度である。 Next, the mechanism of the resistance value measuring method of the present embodiment will be described in detail.
As shown in FIG. 1, when a forward current I flows from the terminal T1 toward the terminal T2, the voltage V between the terminal T1 and the terminal T2 is set to a voltage Va between the terminals of the diode Di and a terminal of the resistor R. A value obtained by adding the voltage Vb between them. Here, the following equation [Equation 2] holds for the diode Di. However, in the expression (2), the I _s saturation current, q is the charge, k is Boltzmann's constant, T is the absolute temperature.

よって、ダイオードＤｉの端子間の電圧Ｖａは、次式〔数３〕で表される。 Therefore, the voltage Va between the terminals of the diode Di is expressed by the following equation [Formula 3].

また、抵抗Ｒの端子間の電圧Ｖｂは、抵抗Ｒの抵抗値をＲ_ｍとすると、Ｖｂ＝Ｒ_ｍ×Ｉであるため、端子Ｔ１と端子Ｔ２との間の電圧Ｖと順方向電流Ｉとの関係式は、次式〔数４〕で表される。また、〔数４〕で表される電圧Ｖと順方向電流Ｉとの特性を図２に示す。 Further, the voltage Vb between terminals of the resistor R, when the resistance value of the resistor R and R _m, because it is Vb = R _m × I, and a voltage V between the terminals T1 and T2 and the forward current I Is expressed by the following equation [Equation 4]. FIG. 2 shows the characteristics of the voltage V and the forward current I expressed by [Equation 4].

従って、端子Ｔ１から端子Ｔ２に向けて順方向電流Ｉ_１、Ｉ_２、Ｉ_３をそれぞれ流した際に、端子Ｔ１と端子Ｔ２との間にそれぞれ発生する電圧Ｖ_１、Ｖ_２、Ｖ_３は、次式〔数５〕で表される。 Therefore, when forward currents I ₁ , I ₂ , and I ₃ are respectively flowed from the terminal T1 to the terminal T2, the voltages V ₁ , V ₂ , and V ₃ generated between the terminals T1 and T2 are respectively Is expressed by the following equation [Equation 5].

そして、〔数５〕に基づいて、Ｖ_２−Ｖ_１と、Ｖ_３−Ｖ_２とをそれぞれ計算すると、次式〔数６〕を得ることができる。 Then, when V ₂ −V ₁ and V ₃ −V ₂ are calculated based on [Equation 5], the following equation [Equation 6] can be obtained.

ここで、順方向電流Ｉ_２が順方向電流Ｉ_１のｎ_ａ倍（Ｉ_２＝ｎ_ａ×Ｉ_１）、順方向電流Ｉ_３が順方向電流Ｉ_１のｎ_ｂ倍（Ｉ_３＝ｎ_ｂ×Ｉ_２）とし、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_３＝Ｖ_３−Ｖ_２、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_３＝Ｉ_３−Ｉ_２とそれぞれすると、ΔＶ_２と、ΔＶ_３とは、次式〔数７〕で表される。 Here, _{n a} multiple of the forward current _{I 2} forward current _{_{_{I 1 (I 2 = n a}}} × I 1), the forward current _{I 3} in the forward current _{I 1} _{n b} times _(I 3 = _{n b} × I ₂ ), ΔV ₂ = V ₂ −V ₁ , ΔV ₃ = V ₃ −V ₂ , ΔI ₂ = I ₂ −I ₁ , ΔI ₃ = I ₃ −I ₂ , respectively, ΔV ₂ and ΔV ₃ is expressed by the following equation [Equation 7].

〔数７〕において、ｎ＝ｎ_ａ＝ｎ_ｂとすると、右辺の電荷ｑとボルツマン定数ｋと絶対温度Ｔとを用いた項は上下の式で同一となる。従って、ΔＶ_３−ΔＶ_２は、ΔＩ_２とΔＩ_３とを用いて、次式〔数８〕で表され、抵抗Ｒの抵抗値Ｒ_ｍは、上述の〔数１〕で求められる。 In [Expression 7], if n = n _a = n _b , the terms using the charge q, the Boltzmann constant k, and the absolute temperature T on the right side are the same in the upper and lower equations. Therefore, ΔV ₃ −ΔV ₂ is expressed by the following equation [Equation 8] using ΔI ₂ and ΔI _3, and the resistance value R _m of the resistor R is obtained by the above [Equation 1].

すなわち、Ｉ_２＝ｎ_ａ×Ｉ_１、Ｉ_３＝ｎ_ｂ×Ｉ_２、ｎ＝ｎ_ａ＝ｎ_ｂの条件下で端子Ｔ１と端子Ｔ２との間のＶ−Ｉ特性を３点測定することで、ダイオードＤｉと直列に接続された抵抗Ｒの抵抗値Ｒ_ｍを、電荷ｑとボルツマン定数ｋと絶対温度Ｔと飽和電流Ｉ_ｓとをキャンセルして正確に算出することができる。 That is, three points of VI characteristics between the terminal T1 and the terminal T2 are measured under the conditions of I ₂ = n _a × I ₁ , I ₃ = n _b × I ₂ , and n = n _a = n _b in the resistance value R _m of the connected resistor R to the diode Di series can be calculated accurately to cancel the charge q and the Boltzmann constant k and absolute temperature T and the saturation current I _s.

本実施の形態の抵抗値測定方法に基づいて抵抗Ｒの抵抗値Ｒ_ｍを求めたシミュレーション結果を図３に示す。
２２Ωと２１０Ωとの２種類の抵抗Ｒで、本実施の形態の抵抗値測定方法に基づくシミュレーションを行った。また、可変電流源１で設定する電流値Ｉの測定電流レンジを大電流領域（〜１５０ｍＡ）と小電流領域（１ｍＡ以下）とに設定し、それぞれでシミュレーションを行った。なお、大電流領域では、ｎ＝５とし、Ｉ_１＝６ｍＡ、Ｉ_２＝５×Ｉ_１＝３０ｍＡ、Ｉ_３＝５×Ｉ_２＝１５０ｍＡとした。さらに、小電流領域では、ｎ＝３とし、Ｉ_１＝１００μＡ、Ｉ_２＝３×Ｉ_１＝３００μＡ、Ｉ_３＝３×Ｉ_２＝９００μＡとした。 The simulation result of obtaining the resistance value R _m of the resistor R on the basis of the resistance value measuring method of the present embodiment shown in FIG.
A simulation based on the resistance value measuring method of the present embodiment was performed with two types of resistors R, 22Ω and 210Ω. Moreover, the measurement current range of the current value I set by the variable current source 1 was set to a large current region (˜150 mA) and a small current region (1 mA or less), and simulations were performed respectively. In the large current region, n = 5, I ₁ = 6 mA, I ₂ = 5 × I ₁ = ₃₀ mA, and I ₃ = 5 × I ₂ = 150 mA. Further, in the small current region, n = 3, I ₁ = 100 μA, I ₂ = 3 × I ₁ = 300 μA, and I ₃ = 3 × I ₂ = 900 μA.

その結果、大電流領域では、誤差の絶対値を従来手法での誤差に比べて１／２程度に抑えることができ、極めて精度よく抵抗Ｒの抵抗値Ｒ_ｍを測定できた。また、小電流領域では、従来手法では誤差が最大で数百％になってしまうのに対し、本実施の形態の抵抗値測定方法では、誤差が最大１６％程度にとどまっており、精度よく抵抗Ｒの抵抗値Ｒ_ｍを測定できた。この結果によると、小電流領域で大幅に誤差を抑えることが可能になっている。従って、本実施の形態の抵抗値測定方法は、大電流を流すことができず、小電流領域を測定電流レンジにしなくてはならない状況下で、特に有効だと考えられる。 As a result, in the large current region, it is possible to suppress the absolute value of the error to about 1/2 as compared with the error of the conventional method, we were able to measure the resistance R _m of the extremely high accuracy resistor R. Also, in the small current region, the maximum error is several hundred percent in the conventional method, whereas in the resistance value measurement method of the present embodiment, the error is only about 16% at maximum. It was measured resistance value _{R m} of R. According to this result, it is possible to greatly suppress errors in a small current region. Therefore, it is considered that the resistance value measuring method of the present embodiment is particularly effective in a situation where a large current cannot be passed and a small current region must be in the measurement current range.

また、Ｉ_２＝ｎ×Ｉ_１、Ｉ_４＝ｎ×Ｉ_３の条件下で端子Ｔ１と端子Ｔ２との間のＶ−Ｉ特性を４点測定して抵抗Ｒの抵抗値Ｒ_ｍを求めるようにしても良い。Ｖ−Ｉ特性を４点測定することで、測定器（可変電流源１、電圧計２）の分解能に起因する誤差を軽減させることができる。 _{_{Also, I 2 = n × I 1}} , I 4 = n × to seek resistance _{R m} of the V-I characteristics were measured four-point resistance R between the terminals T1 and T2 under the condition of _{I 3} Anyway. By measuring the VI characteristics at four points, errors due to the resolution of the measuring instrument (variable current source 1, voltmeter 2) can be reduced.

端子Ｔ１から端子Ｔ２に向けて順方向電流Ｉ_１、Ｉ_２、Ｉ_３、Ｉ_４をそれぞれ流した際に、端子Ｔ１と端子Ｔ２との間にそれぞれ発生する電圧Ｖ_１、Ｖ_２、Ｖ_３、Ｖ_４は、次式〔数９〕で表される。 When forward currents I ₁ , I ₂ , I ₃ , and I ₄ are supplied from the terminal T 1 to the terminal T ₂ , voltages V ₁ , V ₂ , and V ₃ generated between the terminals T 1 and T ₂ , respectively. , V ₄ is expressed by the following equation [Equation 9].

そして、〔数９〕に基づいて、Ｖ_２−Ｖ_１と、Ｖ_４−Ｖ_３とをそれぞれ計算すると、次式〔数１０〕を得ることができる。 Then, when V ₂ −V ₁ and V ₄ −V ₃ are calculated based on [Equation 9], the following equation [Equation 10] can be obtained.

ここで、順方向電流Ｉ_２が順方向電流Ｉ_１のｎ_ａ倍（Ｉ_２＝ｎ_ａ×Ｉ_１）、順方向電流Ｉ_４が順方向電流Ｉ_３のｎ_ｂ倍（Ｉ_４＝ｎ_ｂ×Ｉ_３）とし、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_４＝Ｖ_４−Ｖ_３、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_４＝Ｉ_４−Ｉ_３とそれぞれすると、ΔＶ_２と、ΔＶ_４とは、次式〔数１１〕で表される。 Here, the forward current _{I 2} in the forward current _{I 1} _{n a} fold _{_{_{(I 2 = n a × I}}} 1), the forward current _{I 4} is a forward current _{I 3} _{n b} times _(I 4 = _{n b} XI ₃ ), ΔV ₂ = V ₂ −V ₁ , ΔV ₄ = V ₄ −V ₃ , ΔI ₂ = I ₂ −I ₁ , ΔI ₄ = I ₄ −I ₃ , respectively, ΔV ₂ and ΔV ₄ is expressed by the following equation [Equation 11].

〔数１１〕において、ｎ＝ｎ_ａ＝ｎ_ｂとすると、右辺の電荷ｑとボルツマン定数ｋと絶対温度Ｔとを用いた項は上下の式で同一となる。従って、ΔＶ_４−ΔＶ_２は、ΔＩ_２とΔＩ_４とを用いて、次式〔数１２〕で表される。 In [Equation 11], when n = n _a = n _b , the terms using the charge q, the Boltzmann constant k, and the absolute temperature T on the right side are the same in the upper and lower equations. Therefore, ΔV ₄ −ΔV ₂ is expressed by the following equation [Equation 12] using ΔI ₂ and ΔI ₄ .

従って、設定した第１の電流値Ｉ_１、第２の電流値Ｉ_２、第３の電流値Ｉ_３、第４の電流値Ｉ_４と、電圧値入力部３３によって電圧計２から受け付けた第１の電圧値Ｖ_１、第２の電圧値Ｖ_２、第３の電圧値Ｖ_３、第４の電圧値Ｖ_４とを用い、次式〔数１３〕を算出することで、抵抗Ｒの抵抗値Ｒ_ｍを求めることができる。 Accordingly, the set first current value I ₁ , second current value I ₂ , third current value I ₃ , fourth current value I _4, and the first value received from the voltmeter 2 by the voltage value input unit 33. By using the voltage value V ₁ , the second voltage value V ₂ , the third voltage value V ₃ , and the fourth voltage value V ₄ , the following equation [Equation 13] is calculated, and thus the resistance of the resistor R The value R _m can be determined.

例えば、可変電流源１で設定可能な電流値Ｉの測定電流レンジが小電流領域で１００μＡ〜９００μＡの場合、３点測定の場合には、Ｉ_１＝１００μＡ、Ｉ_２＝３×Ｉ_１＝３００μＡ、Ｉ_３＝３×Ｉ_２＝９００μＡが設定する候補となる。これに対し、４点測定の場合には、Ｉ_１＝１００μＡ、Ｉ_２＝６×Ｉ_１＝６００μＡ、Ｉ_３＝１５０μＡ、Ｉ_４＝６×Ｉ_３＝９００μＡに設定することができる。これにより、ΔＶ_４、ΔＶ_２、ΔＩ_４、ΔＩ_２を大きくとることができる。ΔＶ_４、ΔＶ_２、ΔＩ_４、ΔＩ_２が大きくなると、測定器（可変電流源１、電圧計２）の分解能に起因する誤差を軽減させることができる。 For example, when the measurement current range of the current value I that can be set by the variable current source 1 is 100 μA to 900 μA in the small current region, in the case of three-point measurement, I ₁ = 100 μA, I ₂ = 3 × I ₁ = 300 μA , I ₃ = 3 × I ₂ = 900 μA is a candidate for setting. On the other hand, in the case of 4-point measurement, I ₁ = 100 μA, I ₂ = 6 × I ₁ = 600 μA, I ₃ = 150 μA, and I ₄ = 6 × I ₃ = 900 μA can be set. Thereby, ΔV ₄ , ΔV ₂ , ΔI ₄ , ΔI ₂ can be increased. When ΔV ₄ , ΔV ₂ , ΔI ₄ , and ΔI ₂ are increased, errors due to the resolution of the measuring instrument (variable current source 1, voltmeter 2) can be reduced.

以上説明したように、本実施の形態によれば、ダイオードＤｉと抵抗Ｒとが接続された直列回路に第１の電流値Ｉ_１の順方向電流を流して、直列回路の両端間の電圧を第１の電圧値Ｖ_１として測定する第１の測定工程と、直列回路に第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２の順方向電流を流して、直列回路の両端間の電圧を第２の電圧値Ｖ_２として測定する第２の測定工程と、直列回路に第２の電流値Ｉ_２をｎ倍した第３の電流値Ｉ_３の順方向電流を流して、直列回路の両端間の電圧を第３の電圧値Ｖ_３として測定する第３の測定工程と、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_３＝Ｖ_３−Ｖ_２、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_３＝Ｉ_３−Ｉ_２とし、（ΔＶ_３−ΔＶ_２）／（ΔＩ_３−ΔＩ_２）を直列回路における抵抗Ｒの抵抗値Ｒ_ｍとして算出する抵抗値算出工程と、抵抗値算出工程の算出結果を出力する抵抗値出力工程とを備えている。
この構成により、ダイオードＤｉと抵抗Ｒとが直列接続された２つの端子の情報から、誤差の原因となる電荷ｑとボルツマン定数ｋと絶対温度Ｔと飽和電流Ｉ_ｓとをキャンセルし、正確な抵抗値を求めることができる。 As described above, according to this embodiment, by supplying a first forward current of a current value I ₁ in the series circuit with the diode Di and the resistor R is connected, the voltage across the series circuit flowing a first measuring step of measuring first as a voltage value V _1, the first second forward current of the current value I ₂ which the current I ₁ multiplied by n in the series circuit, both ends of the series circuit the voltage between the second measuring step of measuring a second as the voltage value V _2, by flowing a third forward current of the current value I ₃ to the second current value I ₂ multiplied by n in the series circuit, a third step of measuring the voltage across the series circuit as a third voltage value _{_{_{V 3, ΔV 2 = V 2}}} -V 1, ΔV 3 = V 3 -V 2, ΔI 2 = I 2 -I ₁ , ΔI ₃ = I ₃ −I _2, and (ΔV ₃ −ΔV ₂ ) / (ΔI ₃ −ΔI ₂ ) is the resistance value R of the resistor R in the series circuit. a resistance value calculating step of calculating as _m , and a resistance value outputting step of outputting a calculation result of the resistance value calculating step.
With this configuration, the information of the two terminals and the diode Di and the resistor R are connected in series, to cancel the charge q and the Boltzmann constant k and absolute temperature T causing the error and the saturation current I _s, precise resistance The value can be determined.

さらに、本実施の形態において、ダイオードＤｉと抵抗Ｒとが接続された直列回路に第１の電流値Ｉ_１の順方向電流を流して、直列回路の両端間の電圧を第１の電圧値Ｖ_１として測定する第１の測定工程と、直列回路に第１の電流値Ｉ_１をｎ倍した第２の電流値Ｉ_２の順方向電流を流して、直列回路の両端間の電圧を第２の電圧値Ｖ_２として測定する第２の測定工程と、直列回路に第３の電流値Ｉ_３の順方向電流を流して、直列回路の両端間の電圧を第３の電圧値Ｖ_３として測定する第３の測定工程と、直列回路に第３の電流値Ｉ_３をｎ倍した第４の電流値Ｉ_４の順方向電流を流して、直列回路の両端間の電圧を第４の電圧値Ｖ_４として測定する第４の測定工程と、ΔＶ_２＝Ｖ_２−Ｖ_１、ΔＶ_４＝Ｖ_４−Ｖ_３、ΔＩ_２＝Ｉ_２−Ｉ_１、ΔＩ_４＝Ｉ_４−Ｉ_３とし、（ΔＶ_４−ΔＶ_２）／（ΔＩ_４−ΔＩ_２）を直列回路における抵抗Ｒの抵抗値Ｒ_ｍとして算出する抵抗値算出工程と、抵抗値算出工程の算出結果を出力する抵抗値出力工程とを備えている。
この構成により、４回の測定が必要になるが、限られた測定電流レンジ内でΔＶ_４、ΔＶ_２、ΔＩ_４、ΔＩ_２を大きくとることができ、測定器（可変電流源１、電圧計２）の分解能に起因する誤差を軽減させることができる。 Furthermore, in the present embodiment, a forward current having a _first current value I ₁ is passed through a series circuit in which the diode Di and the resistor R are connected, and the voltage across the series circuit is changed to the first voltage value V. _{The first} measurement step of measuring as ₁ and the forward current of the second current value I _{2 obtained} by multiplying the first current value I ₁ by n times through the series circuit are caused to flow, and the voltage across the series circuit is set to the second a second measuring step of measuring a voltage value V ₂ of the series circuit by flowing a third forward current of the current value I _3, measuring the voltage across the series circuit as a third voltage value V ₃ And a forward current having a _fourth current value I _{4 obtained} by multiplying the third current value I ₃ by n times through the series circuit, and the voltage across the series circuit is set to the fourth voltage value. a fourth step of measuring a _{_{_{V 4, ΔV 2 = V 2}}} -V 1, ΔV 4 = V 4 -V 3, ΔI 2 = I 2 I _1, and _{_{_{ΔI 4 = I 4 -I 3,}}} (ΔV 4 -ΔV 2) / (ΔI 4 -ΔI 2) and the resistance value calculation step of calculating as a resistance value _{R m} of the resistor R in series circuit, the resistance value A resistance value output step for outputting a calculation result of the calculation step.
With this configuration, four measurements are required, but ΔV ₄ , ΔV ₂ , ΔI ₄ , ΔI ₂ can be increased within a limited measurement current range, and the measuring instrument (variable current source 1, voltmeter The error due to the resolution of 2) can be reduced.

なお、本発明が上記各実施の形態に限定されず、本発明の技術思想の範囲内において、各実施の形態は適宜変更され得ることは明らかである。また、上記構成部材の数、位置、形状等は上記実施の形態に限定されず、本発明を実施する上で好適な数、位置、形状等にすることができる。なお、各図において、同一構成要素には同一符号を付している。 Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in practicing the present invention. In each figure, the same numerals are given to the same component.

１可変電流源
２電圧計
３抵抗値算出装置
１０抵抗値測定装置
３１操作部
３２電流値設定部
３３電圧値入力部
３４抵抗値算出部
３５出力部 DESCRIPTION OF SYMBOLS 1 Variable current source 2 Voltmeter 3 Resistance value calculation apparatus 10 Resistance value measurement apparatus 31 Operation part 32 Current value setting part 33 Voltage value input part 34 Resistance value calculation part 35 Output part

Claims

A first measurement process in which a forward current having a _first current value I1 is passed through a series circuit in which a diode and a resistor are connected, and a voltage across the series circuit is measured as a _first voltage value V1. When,
A forward current having a _second current value I _{2 obtained} by multiplying the first current value I ₁ by n is passed through the series circuit, and a voltage across the series circuit is measured as a _second voltage value V ₂ . A second measuring step;
A forward current of the third current value I ₃ to the second current value I ₂ multiplied by n in the series circuit, measuring the voltage across the series circuit as a third voltage value V ₃ A third measuring step;
ΔV ₂ = V ₂ −V ₁ , ΔV ₃ = V ₃ −V ₂ , ΔI ₂ = I ₂ −I ₁ , ΔI ₃ = I ₃ −I _2, and (ΔV ₃ −ΔV ₂ ) / (ΔI ₃ −ΔI) ₂ ) calculating a resistance value as a resistance value of the resistor in the series circuit;
And a resistance value output step of outputting a calculation result of the resistance value calculation step.

A first measurement process in which a forward current having a _first current value I1 is passed through a series circuit in which a diode and a resistor are connected, and a voltage across the series circuit is measured as a _first voltage value V1. When,
A forward current having a _second current value I _{2 obtained} by multiplying the first current value I ₁ by n is passed through the series circuit, and a voltage across the series circuit is measured as a _second voltage value V ₂ . A second measuring step;
A third measuring step of passing a forward current having a _third current value I ₃ through the series circuit and measuring a voltage across the series circuit as a third voltage value V ₃ ;
A forward current having a _fourth current value I _{4 obtained} by multiplying the third current value I ₃ by n is passed through the series circuit, and a voltage across the series circuit is measured as a _fourth voltage value V ₄ . A fourth measuring step;
ΔV ₂ = V ₂ −V ₁ , ΔV ₄ = V ₄ −V ₃ , ΔI ₂ = I ₂ −I ₁ , ΔI ₄ = I ₄ −I ₃ and (ΔV ₄ −ΔV ₂ ) / (ΔI ₄ −ΔI) ₂ ) calculating a resistance value as a resistance value of the resistor in the series circuit;
And a resistance value output step of outputting a calculation result of the resistance value calculation step.

A program for causing a computer to execute a resistance value measuring method for measuring a resistance value of a resistor in the series circuit based on information between both ends of the series circuit in which a diode and a resistor are connected,
The program causes the computer to
The series circuit includes a first current value I ₁ , a second current value I _{2 obtained} by multiplying the first current value I ₁ by n, and a third current value I obtained by multiplying the second current value I ₂ by n times. _Of the first voltage value V ₁ , the second voltage value V ₂ , and the third voltage value V ₃ across the series circuit respectively measured by the voltmeter when each of the _three forward currents flows. A voltage value input unit for receiving each input;
ΔV ₂ = V ₂ −V ₁ , ΔV ₃ = V ₃ −V ₂ , ΔI ₂ = I ₂ −I ₁ , ΔI ₃ = I ₃ −I _2, and (ΔV ₃ −ΔV ₂ ) / (ΔI ₃ −ΔI) ₂ ) a resistance value calculating unit that calculates the resistance value of the resistor in the series circuit;
A program that operates as an output unit that outputs a calculation result by a resistance value calculation unit.

A program for causing a computer to execute a resistance value measuring method for measuring a resistance value of a resistor in the series circuit based on information between both ends of the series circuit in which a diode and a resistor are connected,
The program causes the computer to
In the series circuit, a first current value I ₁ , a second current value I _{2 obtained} by multiplying the first current value I ₁ by n, a third current value I ₃ , and the third current value I ₃ are set to n A first voltage value V ₁ , a second voltage value V ₂ across the series circuit respectively measured by a voltmeter when a forward current having a multiplied fourth current value I ₄ is passed. A voltage value input unit for receiving inputs of the third voltage value V ₃ and the fourth voltage value V ₄ , respectively;
ΔV ₂ = V ₂ −V ₁ , ΔV ₄ = V ₄ −V ₃ , ΔI ₂ = I ₂ −I ₁ , ΔI ₄ = I ₄ −I ₃ and (ΔV ₄ −ΔV ₂ ) / (ΔI ₄ −ΔI) ₂ ) a resistance value calculating unit that calculates the resistance value of the resistor in the series circuit;
A program that operates as an output unit that outputs a calculation result by a resistance value calculation unit.