JPH0175875U - - Google Patents
Info
- Publication number
- JPH0175875U JPH0175875U JP1987171841U JP17184187U JPH0175875U JP H0175875 U JPH0175875 U JP H0175875U JP 1987171841 U JP1987171841 U JP 1987171841U JP 17184187 U JP17184187 U JP 17184187U JP H0175875 U JPH0175875 U JP H0175875U
- Authority
- JP
- Japan
- Prior art keywords
- resistor
- transistor
- terminal
- power source
- collector terminal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001514 detection method Methods 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 3
Landscapes
- Measurement Of Current Or Voltage (AREA)
Description
第１図は本考案の一実施例の回路図、第２図は
ループ電流検出回路の電流検出特性図、第３図は
従来のループ電流検出回路の一例の回路図である
。
１……第１の電源、２，２ａ……ループ電流検
出回路、３……負荷、Ｒ１〜Ｒ４……第１〜第４
の抵抗、ＰＣ１……ホトカプラ、Ｑ１，Ｑ２……
第１、第２のトランジスタ、ＺＤ１……定電圧ダ
イオード、Ｉｏ……ループ電流、Ｖｄ……ループ
電流検出電圧、Ｖｃｃ……第２の電源。
FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a current detection characteristic diagram of a loop current detection circuit, and FIG. 3 is a circuit diagram of an example of a conventional loop current detection circuit. 1... First power supply, 2, 2a... Loop current detection circuit, 3... Load, R1 to R4... First to fourth
Resistor, PC1... photocoupler, Q1, Q2...
First and second transistors, ZD1... Constant voltage diode, Io... Loop current, Vd... Loop current detection voltage, Vcc... Second power supply.
Claims (1)
と第２の抵抗と、この第１と第２の抵抗のそれぞ
れ一端の接続点にベース端子が接続されエミツタ
端子が定電圧ダイオードを介して前記第２の抵抗
の他端に接続されコレクタ端子が第３の抵抗を介
して前記第１の抵抗の他端に接続される第１のト
ランジスタと、前記第３の抵抗の両端に発光部の
入力端が接続され受光部の出力端が第２のトラン
ジスタのベース端子とコレクタ端子に接続される
ホトカプラと、第２の電源の一端と前記第２のト
ランジスタのエミツタ端子に接続される第４の抵
抗とを有することを特徴とするループ電流検出回
路。 A first power source connected in series between a first power source and a load.
and a second resistor, a base terminal is connected to the connection point of one end of each of the first and second resistors, an emitter terminal is connected to the other end of the second resistor via a constant voltage diode, and a collector terminal is connected to the other end of the second resistor. a first transistor connected to the other end of the first resistor via a third resistor; an input end of a light emitting section is connected to both ends of the third resistor; an output end of the light receiving section is connected to a second transistor; A loop current detection circuit comprising: a photocoupler connected to a base terminal and a collector terminal of a transistor; and a fourth resistor connected to one end of a second power supply and an emitter terminal of the second transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987171841U JPH0175875U (en) | 1987-11-09 | 1987-11-09 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987171841U JPH0175875U (en) | 1987-11-09 | 1987-11-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0175875U true JPH0175875U (en) | 1989-05-23 |
Family
ID=31463846
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1987171841U Pending JPH0175875U (en) | 1987-11-09 | 1987-11-09 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0175875U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0650981U (en) * | 1992-05-22 | 1994-07-12 | 株式会社マツショウ | Lamp flashing device |
-
1987
- 1987-11-09 JP JP1987171841U patent/JPH0175875U/ja active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0650981U (en) * | 1992-05-22 | 1994-07-12 | 株式会社マツショウ | Lamp flashing device |