Kelvin

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Kelvins Bridge
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• Modified version of Wheatstone's bridge
• measuring range -1 micro ohm to 1 ohm
• Uses a second set of ratio arms
• Called Kelvins double bridge
• Eliminates the effects of contact lead
  resistnace

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For bridge to balance

• Rx R2. R3 / R1
• Rb/ Ra R3 /R1

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Mega Ohm bridge

• used to measure high resistance
• Range 0.1 to 10 6 M O
• Accuracy - 3

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Eqlt. For high resistance

• A high resistance
• Guard terminal to insulator

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Mega ohm meter
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• High gain amplr
• Balancing bridge

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Ac bridges

• Based on Wheatstone bridge principle
• To measure L C
• Appln. In communication complex electronic
  circuits
• Used for phase shifting, providing feed back path
  for oscillators ampr, filtering, measuring
  frequncy

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• I1 Z1 I2 Z3
• I1 Z2 I2 Z4
• Z1/ Z2 Z3 / Z 4
• Z1 Z 4 Z2 Z3

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Similar angle bridge

• Also called Capacitive comparison bridge
• Series Resistance capacitive bridge
• Used to measure impedance of capacitive ckt.
• Independent of frequency

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Thank u
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Similar angle bridge
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Maxwell bridge

• To determine unknown resistance
• With capacitance standard
• (C not affected by external field,cheap, small
  in size)
• Also called Maxwell- Wein bridge
• For measuring L with low Q (lt 10)

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Hay bridge
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• Used to measure R L where resistance is a small
  fraction of reactance Xl.
• Used for coil with high Q
• Replacing capacitor for measurement in similar
  angle bridge
• Opposite Angle bridge

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THANK U