Analysis of Electric Circuits

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Analysis of Electric Circuits
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Electric Circuit

• Electric Circuit
• An interconnection of simple electrical devices
  with at least one closed path in which current
  may flow

Circuit Elements

• Active Elements
• Voltage and Current sources
• Passive Elements
• Resistors, Inductors and Capacitors

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Circuit Elements
Review topics
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Passive Elements

• Resistance (R)
• Property of opposition to flow of current
• The voltage across the resistor is proportional
  to the current flowing through it
• VR IR
• R VR/I
• Unit - Ohm

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Passive Elements

• Inductance (L)
• Property of opposition to the rate of change of
  current
• The voltage induced in the inductor is
  proportional to the rate of change of current
  flowing through it
• eL L (di/dt) N (d?/dt)
• L N (d?/di)
• Unit Henry (H)

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Passive Elements

• Capacitance (C)
• Property which opposes the rate of change of
  voltage
• The capacitive current is proportional to the
  rate of change of voltage across it
• ic C (dv/dt)
• Unit Farad (F).

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Ideal Nature

• Property of the element which does the intended
  work only
• ideal voltage source maintains a prescribed
  voltage regardless of the current in the device.
  Internal resistance Rs 0
• ideal current source maintains a prescribed
  current regardless of the voltage across the
  device. Internal resistance Rs 8
• ideal resistor constraints its voltage and
  current to be proportional to each other. (v
  iR Ohms law)

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Ideal Sources

• Independent Voltage Current Source

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Practical Sources

• Independent Voltage Current Sources

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Source Transformation

• Conversion of Practical Voltage source to Current
  source vice versa

• Voltage Current sources shown in the figure
  are electrically equivalent if
• Vs Ip Rp or (Ip Vs/Rs)
• Rs Rp

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Dependent Sources
Voltage Controlled

• Voltage Controlled Voltage Source (VCVS)

Voltage Controlled Current Source (VCCS)
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Dependent Sources
Current Controlled

• Current Controlled Voltage Source (CCVS)

Current Controlled Current Source (CCCS)