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Summary of Contents for 721A

Page 1: ...P N 294066 October 1968 1982 John Fluke Mfg Co Inc al rights reserved Litho in U S A ...

Page 2: ...ce facility giving full details of the difficulty and include the model number type number and serial number On receipt of this information service data or shipping instructions will be forwarded to you 2 On receipt of the shipping instructions forward the instrument transportation prepaid Repairs will be made at the Service Facility and the instrument returned transportation prepaid SHIPPING TO M...

Page 3: ...721A iii ...

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Page 5: ... 1 4 ELECTRICAL RESOLUTION OF RESISTANCE COMPENSATION 0 1 milliohm MAXIMUM RATIO BETWEEN DIVIDER RESISTANCES 4000 to 1 MAXIMUM ALLOWABLE LEAD RESISTANCE 150 miiliohms MAXIMUM DIVIDER VOLTAGE 1500 volts de or peak ac FINE CONTROL 10 turn 150 milliohm slide wire potentiometer COARSE CONTROL 18 position rotary switch BINDING POSTS Gold plated copper VOLTAGE SWITCH Grounds input voltage terminals to p...

Page 6: ...72 1A Figure 1 1 MODEL 72 1A OUTLINE DRAWING 1 2 ...

Page 7: ...lem 2 Learning the guidelines for handling them 3 Using the procedures and packaging and bench techniques that are recommended The Static Sensitive S S devices are identified in the Fluke technical manual parts list with the symbol The following practices should be followed to minimize damage to S S devices 2 KEEP PARTS IN ORIGINAL CONTAINERS UNTIL READY FOR USE 4 HANDLE S S DEVICES BY THE BODY Pa...

Page 8: ...EVICES ONLY AT A STATIC FREE WORK STATION 10 ONLY ANTI STATIC TYPE SOLDER SUCKERS SHOULD BE USED 11 ONLY GROUNDED TIP SOLDERING IRONS SHOULD BE USED Anti static bags for storing S S devices or pcbs with these devices on them can be ordered from the John Fluke Mfg Co Inc See section 5 in any Fluke technical manual for ordering instructions Use the following part numbers when ordering these special ...

Page 9: ...e balance resistance With the switch in the R STD R TEST position the coarse balance resistance is placed in series with the test di vider with the switch in the R STD R TEST position the coarse balance resistance is placed in series with the standard divider 2 10 LOW BALANCE CONTROLS 2 11 The COARSE control an 18 position switch controls application of the relatively large amounts of resistance i...

Page 10: ...721A Figure 2 1 RATIO SYSTEM CONFIGURATION 2 2 ...

Page 11: ...721A MODEL 332B Figure 2 2 INTERCONNECTION OF UNITS FOR RATIO COMPARISON ...

Page 12: ... are then determined and used to compute the unknown resistance from the formula unknown 1 R2 standard R3 2 20 LEAD RESISTANCE COMPENSATION 2 21 To use the Model 721A for lead compensation it must be connected into the ratio comparison system as shown in Figure 2 2 Figure 2 3 illustrates a schematic diagram of the equipment connections The equipment should be turned on and allowed to warm up for 3...

Page 13: ...d for measurement at calibra tion points must eompensa fce for thermal voltages if optimum accuracy is to be obtained Adjustment of the Model 721A compensates only for voltage drops at the high and low ends of the circuit caused by end and lead resistance it can not compensate for thermal voltages at calibration points because they may vary from one calibration point to the next To make thermal co...

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