PERTEMUAN 9

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PERTEMUAN 9

• JEMBATAN DCAC dan APLIKASINYA

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PENDAHULUAN

• Sirkuit jembatan biasanya digunakan untuk
  mengukur nilai komponen, seperti resistansi,
  induktansi, kapasitansi dan parameter sirkuit
  lainnya
• Keakurasiannya sangat tinggi

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Wheatstone bridge CONTENTS

• Photograph of the instrument
• Simplified schematic of the bridge
  circuit------------------?

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• Operasi dasar
• Measurement errors
• Found in the limiting errors of the three known
  resistors
• Insufficient sensitivity of the null detector
• Changes in resistance of the bridge arms due to
  the heating effect of the current through the
  resistors
• Thermal emfs in the bridge circuit or the
  galvanometer circuit (when low-value resistors
  are being measured)
• Errors due to the resistance of leads and
  contacts exterior to the actual bridge circuit

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Thevenin Equivalent Circuit

• Wheatstone bridge configuration
  --------------------?
• Thevenin resistance looking into terminals c and
  d --------?
• Complete Thevenin circuit, with the galvanometer
  connected to terminals c and d

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• The Thevenin, or open circuit voltage
• The Thevenin resistance
• The galvanometer current

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Kelvin Bridge

• Wheatstone bridge circuit, showing resistance Ry
  of the lead from point m to point n
• Basic Kelvin double bridge circuit
  --------------------------?

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Loop Tests with The Portable Test Set

• Murray-loop test, used for locating a ground
  fault (short circuit) ----------------------------
  -?
• Varley-loop test (a) no.1 (b) no. 2 (c) no.3,
  used to locate grounds, crosses, or short
  circuits in multiconductor cable
• (b)

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Guarded Wheatstone Bridge

• Used for high resistance measurements

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General Form of The AC Bridge
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Comparison Bridges

• Capacitance comparison bridge
• Equating the real terms
• Equating the imaginary terms
• Inductance comparison bridge

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• Inductance comparison bridge with extended
  measurement range
• With the switch in position 1
• With the switch in position 2