CN2497321Y - Switching constant current source earth resistance measuring instrument - Google Patents
Switching constant current source earth resistance measuring instrument Download PDFInfo
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- CN2497321Y CN2497321Y CN 01255678 CN01255678U CN2497321Y CN 2497321 Y CN2497321 Y CN 2497321Y CN 01255678 CN01255678 CN 01255678 CN 01255678 U CN01255678 U CN 01255678U CN 2497321 Y CN2497321 Y CN 2497321Y
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Abstract
A switch power supply constant current source grounding resistance tester for detection of household apparatus and similar apparatus consists of a switch power supply constant current source, a transmission circuit and a display circuit. The tester provides the testing current by adopting the switch power supply constant current source, and implements the division operation by the A/D chip. The tester has the advantages of simple circuit structure and high reliability.
Description
The utility model relates to the Switching Power Supply constant current source earth resistance tester of a kind of household electrical appliance and similar applications electrical equipment, belongs to the electrical instrument field of measuring technique.
It is reported, the kind of the instrument of test electrical equipment stake resistance is a lot of both at home and abroad at present, main production firm produces this type of instrument both at home and abroad, almost all adopts linear constant current circuit that measuring current is provided, and its shortcoming is that conversion efficiency is low, the easy temperature of circuit is too high, reliability is low, and the resistance measurement of most of instrument adopts and to use division circuit earlier, carries out division arithmetic, through the mode of A/D conversion demonstration, its shortcoming is the circuit complexity again.
The purpose of this utility model is to overcome above-mentioned shortcoming, and a kind of reliability height is provided, the simple earth resistance tester of circuit structure.
The purpose of this utility model is achieved in that tester is made up of the instrument face plate of instrument chassis, tape input output terminal device and back plate, the Switching Power Supply constant current source, current sampling resistor plate, transmission circuit plate and the display circuit board that are fixed in the cabinet.The sub-V1 of Switching Power Supply constant current source current output terminal meets case backboard binding post X1, the G1 termination current sampling resistor R0 of Switching Power Supply constant current source, and the current sampling resistor R0 other end meets the connection terminal X2 of case backboard.The voltage signal that is come by case backboard terminal X1, X2 sampling is connected to input end X1, the X2 of transmission circuit; The terminal X3 at current sampling resistor two ends, X4 are connected to input end X3, the X4 of transmission circuit, after transmission circuit is transformed into digital signal, send into display circuit.The transmission circuit plate is connected by lead with the various interface of display circuit board and back plate.When beginning to test, hold flow through measured object and current sampling resistor (R0) by the measuring current that the Switching Power Supply constant current source provides from Switching Power Supply constant current source V1, get back to Switching Power Supply constant current source G1 end.Terminal X1 on the case backboard, the magnitude of voltage at X2 two ends then equals the magnitude of voltage at measured resistance two ends, these two ends are received by lead respectively and are become the X1 that send plate, and the X2 end becomes the X1 that send plate, the X2 end is connecting resistance R2 respectively, R1 connects the input end (2,3) of difference amplifier IC1 (AD623), the output terminal 6 pin connecting resistance R3 of IC1 again, receive input end 3 pin of amplifier IC2 (OP07) again, output terminal 6 pin of IC2 connect adjustable resistance (RP1).The voltage signal at measured resistance two ends is through difference amplifier (IC1) and amplifier (IC2) sampling, and after adjustable resistance (RP1) is decayed, adjustable resistance K terminates to the voltage input end Vin+ of A/D chip (IC4).The magnitude of voltage at current sampling resistor two ends is inserted by lead and becomes X3, the X4 end that send plate, become and send plate X3 connecting resistance R4, insert input end 3 pin of amplifier IC3 (OP07) again, become and send plate X4 to connect power supply ground, the voltage signal at current sampling resistor two ends its output terminal 6 after amplifier IC3 conversion inserts the reference voltage input Vref+ of A/D chip (IC4).By the digital signal of exporting after the conversion of A/D chip, be exactly the ratio of magnitude of voltage and current value, i.e. the resistance value of measured object.This digital signal is directly delivered to the LED display circuit and is shown.
The utlity model has following advantage:
1, the Switching Power Supply constant current source provides measuring current, the conversion efficiency height.
2, resistance calculations adopts the A/D chip to realize division function, and circuit structure is simple.
Fig. 1-the utility model block diagram
Fig. 2-cabinet arrangenent diagram of the present utility model (vertical view)
Fig. 3-constant-current source circuit
Display circuit is sent in Fig. 4-change
1 is the Switching Power Supply constant current source among Fig. 1; 2 is transmission circuit; 3 is display circuit.Constant current source outputs to transmission circuit, and transmission circuit outputs to display circuit.
1,2 is axial flow blower among Fig. 2; 3 is the Switching Power Supply constant current source; 4 is Switching Power Supply constant current source resistance board in addition; 5 is the current sampling resistor plate; 6 is power transformer; 7 is to become to send plate; 8 is display board, is installed in parallel on the panel of cabinet with cabinet panel.The back plate of cabinet is equipped with supply socket, calibrating terminal, fuse.Each wiring board and various interface are connected by lead.
The utility model adopts the Switching Power Supply constant current source of KD14 model among Fig. 3.Constant current source Vj end is constant current source work control end, voltage is when Vj place+and during 12V voltage, constant current source work, output DC flows.The utility model adopts 555 (IC4) circuit to carry out timing controlled, as IC4 (CC7555 chip) when 2 pin are low level, regularly begins, and transistor VT3, the VT4 conducting, constant current source is started working, and timing arrives, transistor VT3, VT4 ends, and constant current source quits work.Constant current source V2 end is the output current reference voltage terminal, voltage is when the V2 place+during 1V, constant current source output 25A DC current, the utility model adopts stabilivolt VD10 and adjustable resistance RP2 and resistance R 15, and R16 series connection back acquisition+1V voltage in parallel is supplied with Switching Power Supply constant current source V2 end.When the test beginning, constant current source V1 output 25A electric current is supplied with the tested product that are connected on back plate connection terminal (X1, X2) by lead, and the current sampling resistor R0 that flows through again gets back to constant current source G1 end.(X1 X2), sends into the input end X1 of transmission circuit, X2 by lead to the voltage at tested stake resistance two ends by back plate connection terminal.The voltage signal at current sampling resistor two ends is sent into the input end X3 of transmission circuit IC3, X4 by lead.
The utility model adopts the A/D chip (IC4) of ICL7135 model to realize division function among Fig. 4.
IC5 (CD4069) is a hex inverter, with resistance R 11, R12 capacitor C 10 forms oscillatory circuit, 6,9,11, the 13 pin clock signals of IC5 are supplied with the CL pin of IC4 (ICL7135), 8,10, the 12 output termination capacitor C 9 of IC5 are supplied with IC4 (ICL7135) V-pin through half-wave voltage-multiplying circuit (being made up of capacitor C 6～C8 and diode VD2～VD5) generation-5V voltage.The voltage at measured resistance two ends is sent into by lead and is become difference amplifier IC1 (AD623) input end (2,3 pin) that send plate, and voltage input end Vin+ and the Vin-of IC4 (ICL7135) sent in process amplifier IC2 (OP07) and adjustable resistance RP1 decay.The magnitude of voltage at current sampling resistor two ends by amplifier IC3 (OP07) be amplified to+1V about, send into reference voltage input Vref and the Com of IC4 (ICL7135).The Vin-pin of ICL7135 is by resistance R 10 and Com pin short circuit.For IC4 A/D chip, the digital signal of output equals input voltage value Vin divided by reference voltage value Vref.In the utility model, the output digital signal of ICL7135 just equals tested stake resistance both end voltage signal divided by current value, realizes division function thus, draws the grounding resistance of actual tested product, sends into LED and shows.
Claims (2)
1, be used to test the earth resistance tester of household electrical appliance and similar applications electrical equipment, it is by instrument chassis, the instrument face plate and the back plate that have input-output unit, be fixed on the Switching Power Supply constant current source in the instrument chassis, the current sampling resistor plate, become and send plate, compositions such as display board, the current output terminal V1 that it is characterized in that the Switching Power Supply constant current source receives case backboard terminal X1, the terminal G1 of switch constant-current source receives current sampling resistor R0, the current sampling resistor R0 other end is received case backboard terminal X2, the resistive voltage sampling terminal X1 of case backboard, X2 is inserted by lead and becomes the X1 that send plate, the X2 end, the current sample terminal X3 at current sampling resistor two ends in the cabinet, X4 is inserted by lead and becomes the X3 that send plate, the X4 end, become and send plate X1, the X2 end is connecting resistance R2 respectively, R1, receive the input end (2 of difference amplifier IC1 (AD623) again, 3), the output terminal 6 pin connecting resistance R3 of IC1, receive 3 pin of IC2 (OP07) again, output terminal 6 pin of IC2 connect adjustable resistance (RP1), the K of adjustable resistance terminates to the voltage input end Vin+ of IC4 (ICL7135) chip, become and send plate X3 terminating resistor R4 to insert input end 3 pin that become the IC3 (OP07) that send plate again, become and send plate X4 termination circuit power supply ground, output terminal 6 pin of IC3 (OP07) meet the reference voltage terminal Vref+ of IC4 (ICL7135) chip.
2, tester according to claim 1 is characterized in that the IC4 integrated package that resistance measurement is used is to adopt the A/D chip, realizes division function.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01255678 CN2497321Y (en) | 2001-09-13 | 2001-09-13 | Switching constant current source earth resistance measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01255678 CN2497321Y (en) | 2001-09-13 | 2001-09-13 | Switching constant current source earth resistance measuring instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2497321Y true CN2497321Y (en) | 2002-06-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01255678 Expired - Fee Related CN2497321Y (en) | 2001-09-13 | 2001-09-13 | Switching constant current source earth resistance measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2497321Y (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103163382A (en) * | 2013-03-12 | 2013-06-19 | 中国铁路通信信号上海工程集团有限公司 | Real-time online measurement system and method for resistance of ground wire |
| CN103207342A (en) * | 2013-01-10 | 2013-07-17 | 嘉兴电力局 | Ground intelligent pre-warning device for overhauling test |
| CN103207331A (en) * | 2013-03-12 | 2013-07-17 | 中国铁路通信信号上海工程集团有限公司 | System and method for monitoring damaged on-off quantity of surge protection device and ground resistance online in real time |
| CN107907745A (en) * | 2017-12-31 | 2018-04-13 | 广东立信防雷科技有限公司 | A kind of earth resistance tester and its grounding monitor method |
-
2001
- 2001-09-13 CN CN 01255678 patent/CN2497321Y/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103207342A (en) * | 2013-01-10 | 2013-07-17 | 嘉兴电力局 | Ground intelligent pre-warning device for overhauling test |
| CN103207342B (en) * | 2013-01-10 | 2016-09-07 | 嘉兴电力局 | A kind of checking experiment grounding intelligent prior-warning device |
| CN103163382A (en) * | 2013-03-12 | 2013-06-19 | 中国铁路通信信号上海工程集团有限公司 | Real-time online measurement system and method for resistance of ground wire |
| CN103207331A (en) * | 2013-03-12 | 2013-07-17 | 中国铁路通信信号上海工程集团有限公司 | System and method for monitoring damaged on-off quantity of surge protection device and ground resistance online in real time |
| CN103207331B (en) * | 2013-03-12 | 2015-07-29 | 中国铁路通信信号上海工程集团有限公司 | The switching value that lightning protection device damages and stake resistance real time on-line monitoring system and method |
| CN103163382B (en) * | 2013-03-12 | 2016-04-06 | 中国铁路通信信号上海工程集团有限公司 | Line resistance real-time online measuring system and method |
| CN107907745A (en) * | 2017-12-31 | 2018-04-13 | 广东立信防雷科技有限公司 | A kind of earth resistance tester and its grounding monitor method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |