DC Circuits 05 - Resistors and Capacitors in Series & Parallel

OPENING QUESTIONS: Please review your working model with your groupies... where is your model strong, where is it weak?

1) How does charge change through a circuit? (caps, resistors, series, parallel)

2) How does current change through a circuit? (caps, resistors, series, parallel)

3) How does voltage change through a circuit? (caps, resistors, series, parallel)

OBJECTIVE: I will finalize my working model to calculate circuit values during today's class

TERMS:

  • Capacitor - two charged surfaces that can store electrical energy
  • Resistor - an object in an electric circuit which interferes with the flow of electrons through that circuit.
  • Series: occurs when items in a circuit are connected in a line
  • Parallel: occurs when items in a circuit
  • ElectroMotive Force = EMF= ε=Voltage

UNITS:

  • Capacitance = C
    • (SI Units "farads" = f)
  • EMF = ε =Voltage generated inside a battery
    • (SI Units = "Voltage or Volts"="V")
  • Voltage = ∆V = Voltage available to a circuit
    • (SI Units = "Voltage or Volts"="V")
  • Current = I = Current through an electrical circuit
    • (SI Units = "amperes or Amps"="A")
  • Ohms = R=resistance =
    • (SI Units = "ohms" = Ω)
  • Power = P = I2R
    • (SI Units = "Watts" = W)

FORMULAE:

      • ε=IR (ε = ElectroMotive Force) = Total *oomph* inside the battery, it is not generally equal to the voltage output by the battery because of the internal resistance inside the battery
      • ∆V = IR = "Ohm's Law": (We'll use this UNLESS EMF is given)
      • P = I2R = Power
      • The sum of the voltages around ANY loop in a circuit = 0.

════════════════════

For each of the next two images please review the plan by which we attacked circuit analysis yesterday....

 

 

 

 

 

Hopefully you came up with:

1) Draw arrows

2) Reduce the circuit

3) Find I1

4) Use Kirchoff (1) to write a circuit equation. For example: I1 = I2 + I3

5) Use Kirchoff (2) to write an equation that shows voltage drops going to zero around ANY loop that includes the battery(s).

Straightforward:

Downright NASTY: (4 equations and 4 unknowns? Or is it 5 equations and 5 unknowns.... I dunno!)

If time permits, review my annotated responses from Tuesday's work
STUDY GUIDE: