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IM 2769-10E

 iii 

■ Since mishandling the instrument can result in an accident, such as an electric shock, 

 

that may injure the operator or damage the instrument, be sure to observe  

the following instructions.

CAUTION

 

● Batteries

• Do not use a mixture of different types of batteries or a mixture of old and new batteries. 

  If the instrument will not be used for a prolonged period, remove the batteries before storage.

  The battery fluid will leak more readily during long-term storage, resulting in an instrument  

malfunction.

Summary of Contents for 2769

Page 1: ...2769 Portable Double Bridge User s Manual IM 2769 10E IM 2769 10E 6th Edition Oct 2017 YMI ...

Page 2: ... PIM 113 01Z2 Inquiries List of worldwide contacts Notice regarding This Document and User s Manual The information covered in this User s manual is subject to change without prior notice Every effort has been made to ensure accuracy in the preparation of this manual Should any errors or omissions come to your attention however please inform YOKOGAWA accordingly YOKOGAWA is by no means liable for ...

Page 3: ...s If a crack appears in the instrument after it has been accidentally dropped or bumped the safety purpose insulation may be damaged By all means do not use the instrument but ask the manufacture for repair Connection To avoid electric shock be sure to apply protective grounding to the grounding terminal Install a protection fuse as shown in the example of measurement Measurement Always maintain t...

Page 4: ...t be sure to observe the following instructions CAUTION Batteries Do not use a mixture of different types of batteries or a mixture of old and new batteries If the instrument will not be used for a prolonged period remove the batteries before storage The battery fluid will leak more readily during long term storage resulting in an instrument malfunction ...

Page 5: ...nt 7 4 3 Accessories 9 5 CAUTIONS 10 5 1 Cautions for Operation 10 5 2 Cautions for Maintenance 10 5 3 Calibration 10 5 3 1 General Check 10 5 3 2 Check on Operation 10 5 3 3 Calibration of Standard Resistor 11 5 3 4 Calibration of Measuring Arm Dial 11 6 PRINCIPLE OF OPERATION 12 6 1 Basic Principles 12 6 2 Error 12 6 2 1 Error due to Current Lead 12 6 2 2 Error due to Potential Lead 13 7 CIRCUIT...

Page 6: ...1 mΩ at ambient temperature 5 to 35 C and the lead resistance between C2 terminals and Rx is less than 20 mΩ Measuring Dial 1 00 to 11 00 Ω 0 05 Ω minimum division 0 0001 0 001 0 01 0 1 1 10 0 1Ω mΩ to 1 1 mΩ 1 mΩ to 11 mΩ 0 01 Ω to 0 11 Ω 0 1 Ω to 1 1 Ω 1 Ω to 11 Ω 10 Ω to 110 Ω 0 01 Ω 0 1 Ω 1 Ω 10 Ω 100 Ω 1000 Ω 10 A 3 A 1 A 0 3 A 0 1 A 0 01 A 0 1 0 1 0 1 0 1 0 1 0 1 Multiply Measuring range Res...

Page 7: ... dry cell UM 1 or SUM 1 two cell are parallel connected Max current supply approx 1 to 2 A Battery life more than 1200 measurement 50 duty cycle 15 sec maximum on time Operating Temperature and Humidity Range 5 to 35 C Less than 85 Dimensions Approx 182 226 118 mm excluding handle and rubber feet Approx 196 226 130 mm including handle and rubber feet Weight Approx 2 6 kg 5 7lbs Accessories Plug A1...

Page 8: ...7 0 8 0 7 5 8 5 6 0 2 0 1 5 1 0 11 0 1 0 5 1 0 0 9 5 9 0 Front Panel Fig 3 1 Front Panel 1 Measuring Dial This dial is used to adjust the measuring arm 2 Multiplying Factor Switching Plug The multiplying factor is selected by this plug 3 Battery Switch This switch turns on off the power to the bridge 4 Galvanometer Button Switch The galvanometer is connected to the bridge by depressing this switch...

Page 9: ...tery is used to supply power to the bridge these terminals are short circuited by the short bar 7 EXT BA Terminals When an external power supply is used these terminals are short circuited by the short bar 8 Rx Terminals An unknown resistance is connected to these terminals The Rx terminals consist of current terminals C1 C2 and potential terminals P1 and P2 9 P2S Terminal This is one of the poten...

Page 10: ...lose the cover push the clamping plate in the arrow direction fit the edge A A with the groove of the instrument body and depress the cover The stopper will lock the cover in its place Since two batteries are used in parallel connection replace them with two new ones at a time Note that use of old battery in combination with new one will result in short battery life Fig 3 2 Removal of the Battery ...

Page 11: ...rnal battery so as not to allow current flow in the instrument exceeding the value indicated above the MULTIPLY jack and external standard resistor OFF GA OFF BA ON GA Ω MULTIPLY MAX CURRENT A 10 0 01 0 1 0 3 1 3 1 0 1 0 01 0 001 EXT BA G2 CH G1 G0 C2S C2 P2 C1 P1 P2S P1S A A INT BA EXT BA Rx Ammeter Battery Slide Resistor Fig 3 4 a Connection for External Battery C2 P2 C1 P1 Rx Rx Fig 3 4 b Conne...

Page 12: ... for Measurement 1 Select a multiplying factor by using the plug to fit the approximating value of the unknown resistance according to Table 4 1 Rx MULTIPLY 0 1 to 1 1 mΩ 1 to 11 mΩ 10 to 110 mΩ 0 1 to 1 1 Ω 1 to 11 Ω 10 to 110 Ω 0 0001 0 001 0 01 0 1 1 10 When using 2771 Table 4 1 2 Turn the BA switch ON 3 Set the measuring dial to a position near the center push the GA button switch momentarily ...

Page 13: ...ty dial to GA OFF position 6 When it is desired to measure the resistance below 1 mΩ to 0 1 mΩ connect the 2771 standard resistor to the instrument as shown in Fig 4 1 In this case the plug should be removed The unknown resistance Rx is calculated from the following equation Rx Dial indication Value of external standard resistor Ω 1 100 2769 Portable Double Bridge 2771 Standard Resistor 0 01 Ω Rx ...

Page 14: ... 2 Measuring Cords 2 Clamping Device 275400 This clamping device is used for the measurement of a bar resistance of unit length or conductivity length from terminal P1 to terminal P2 approx 500 mm C1 P1 P2 C2 Fig 4 3 Clamping Device 3 Ammeter When an ammeter is used for monitoring current through Rx remove the short bar INT BA or EXT BA terminals and the ammeter is connected to these terminals For...

Page 15: ...f the slide resistor Avoid using sandpaper or the like when cleaning 2 Remove the self contain batteries when the instrument is stored for a long period 3 The panel and case of this double bridge are made of ABS resin and has sufficient mechanical strength However they are low resistive against heat and chemicals An organic solvent such as lacquer thinner should be strictly avoided when cleaning t...

Page 16: ...nt value should be 1 3 the value indicated on the MULTIPLY jacks For this calibration use of the 2752 precision double bridge is recommended 5 3 4 Calibration of Measuring Arm Dial Connect a calibrated resistor 1000 Ω as an external resistor and then connect a variable standard resistor 10 Ω to 110 Ω whose accuracy is 0 1 or better to the Rx arm in the 10 range and measure its resistance The calib...

Page 17: ...ned so that the fixed resistors and slide resistors have the following relationship 6 2 N n and M m Therefore From equation 6 1 X S 0 N M n m N M In other words the low resistance X can be accurately measured without influenced by the lead resistance E G N n m M Px C2 Ps X S Fig 6 1 Theoretical Circuit Diagram 6 2 Error 6 2 1 Error due to Current Lead Practically N M n m is not perfectly zero but ...

Page 18: ... directly related to this error but the ratio N M has relation to the error Therefore when the lead resistance is present on the N arm the influence of this can be cancelled by adding a lead resistance to the M arm This is expressed by the following equation 6 4 X S S 1 M M N N N N N N M M on condition that 1 M M 1 N M In Model 2796 double bridge a resistance to act as can be connected to the term...

Page 19: ... and n arms there are provided no terminals such as corresponding to P2S The influence of the lead resistance and upon the m and n arms can be neglected if the value of is determined sufficiently smaller than that of S 1 0 5 1 0 0 1 0 2 3 4 5 6 7 8 9 10 11 0 5 e r r o r N Ω Dial Scale Lead Resistance at Potential Terminal Fig 6 2 Error due to Potential Lead ...

Page 20: ...1 S1 BA1 BA2 S3 S2 R11 R13 R9 RV2 RV1 0 1 Ω 13 24 Ω 120 Ω 390 Ω 1897 Ω R8 1897 Ω R10 R12 120 Ω R6 13 24 Ω R14 0 3 Ω R105 18 Ω R104 1 MΩ 10 kΩ R103 100 Ω R102 1 kΩ 390 Ω 1 Ω 10 Ω 100 Ω 1000 Ω P2 P1S P1 P1S P2S C2S C2 P2S C2S C2 C1 R2 R3 R4 R5 10 1 0 01 Ω 0 1 0 01 0 001 EXT BA Rx A A INT BA EXT BA ...

Page 21: ...Printed in Japan ...

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