电子电路 第一章

Introduction and Lumped Circuit Abstraction

• What is engineering?

  1. Purposeful use of science

• What is 6.002 about?

  1. Gainful employment of Maxwell’s equations
  2. From electrons to digital gates and op-amps
  3. 

Lumped Matter Disciplines

• Lumped Matter Discipline(LMD) Or self imposed constraints:

  1. ∂θB∂t=0
     outside
  2. ∂q∂t=0
     inside elements bulb, wire, battery

• Lumped circuit abstraction applies when elements adhere to the lumped matter discipline.

• Replace the differential equations with simple algebra using lumped circuit abstraction(LCA)

• Kirchhoff’s Voltage Law (KVL): The sum of the voltages in a loop is 0.

  1. KVL : ∑jvj=0 loop
  2. KCL:∑jij=0 node
• Kirchhoff’s Current Law (KCL): The sum of the currents into a node is 0.

Basic Circuit Analysis Method

• LMD(Lumped Matter Discipline):Constraints we impose on ourselves to simplify our analysis.
• lumped circuit element
• 
  Method 1: Basic KVL,KCL method of Circuit analysis
  
  1. find all element v’s and i’s
  2. write element v-i relationships(from lumped circuit abstraction)
  3. write KCL for all nodes.
  4. write KVL for all loops.
• 
  Method 2–Apply element combination rules
• 
  Method 3–Node analysis Particular application of KVL,KCL method
• 
  
  1. Select reference node(ground) from which voltages are measured.
  2. Label voltages of remaining nodes with respect to ground.These are the primary unknowns.
  3. Write KCL for all but the ground node,substituting device laws and KVL.
  4. Solve for node voltages.
  5. Back solve for branch voltages and currents.