Circuits Lecture 9 Thevenin and Norton Theorem 2

Circuits Lecture 9: Thevenin and Norton Theorem (2) 李宏毅 Hung-yi Lee

Review - Thevenin and Norton Theorem Thevenin Theorem Two Terminal Network Norton Theorem

Review - Thevenin and Norton Theorem Two Terminal Network = Two Terminal Network The same concept is applied on isc.

Review - Thevenin and Norton Theorem suppress Two Terminal Network

Review - Thevenin and Norton Theorem Find voc Find isc Two Terminal Network Is it correct?

Outline • Maximum Power Transfer • Chapter 3. 1 • Application of Thevenin Theorem

Review: Power Negative Communed Power = Supplied Power • Consumed Power A + - B reference current should flow from “+” to “-” • Suppied Power A + - B reference current should flow from “-” to “+”

Ideal Sources i-v curse Larger power Ideal sources can supply unlimited power. Larger power

Real Source • Real voltage sources cannot supply unlimited power i-v characters for real voltage source Real voltage source = Ideal voltage source + resistor

Real Source • Real current sources cannot supply unlimited power i-v characters for real current source Real current source = Ideal current source || resistor

Maximum power transfer power Device (Load) Power consumed by Rs Real source Power consumed by RL Rs is fixed, increase RL

Maximum power transfer to (consumed by) a load resistance requires RL = Rs: (Only 25%) Power consumed by RL

Maximum power transfer RL is a variable Find RL which maximizes PL When d. PL/d. RL=0, PL is maximum d. PL/d. RL=0, when Rs=RL

Power-transfer efficiency Eff=50%

Maximum power transfer When RL = Rs

Maximum power transfer Signals from Sound Card Audio Amplifier Find a speaker that can gain sufficient power http: //ming-shian. blogspot. tw/2013/05/radio-teardown. html

Maximum power transfer Difficult to compute the power Input audio signal Audio Amplifier http: //angelfire. com/ab 3/mjramp/index. html Thevenin Theorem

Maximum power transfer Sound Card + Audio Amplifier (speaker) Power consumed by RL

Application of Thevenin • Which value of R can absorb maximum power? Find the power. + - + - p. R is maximum when dp. R/d. R=0

Application of Thevenin • Which value of R can absorb maximum power? Find the power. + - + - Have to find voc

Application of Thevenin • Find voc + + - + - voc -

Application of Thevenin • Use Thevenin Theorem several times + - + - + - -

Application of Thevenin • Use Thevenin Theorem several times + - + + - -

Application of Thevenin • Use Thevenin Theorem several times + - + + - -

Application of Thevenin • Use Thevenin Theorem several times + -

Remind – Exercise 3. 3 • What value of RL should be used to obtain the maximum available power?

Homework • 1 ST ORDER DIFFERENTIABLE EQUATIONS • https: //www. youtube. com/watch? v=2 s 9 z 1 z. LOAJY • 2 ND ORDER DIFFERENTIABLE EQUATIONS • https: //www. khanacademy. org/math/differentialequations/second-order-differential-equations/linearhomogeneous-2 nd-order/v/2 nd-order-linearhomogeneous-differential-equations-1

Thank you!

Appendix – Non-linear Elements

Non-linear Elements (http: //www-inst. eecs. berkeley. edu/~ee 42/sp 03/Lect. Notes/42_05_6. pdf)

Non-linear Elements

Non-linear Elements Which operating regions?

Non-linear Elements