1 / 19

Lecture 12 (parts A & B)

Lecture 12 (parts A & B). Review: Source transformations Maximum power transfer Derivation of maximum power transfer Thévenin theorem examples Operational Amplifiers Related educational materials : Chapters 4.5, 4.6, 5.1-5.4 . Using Source Transformations in Circuit Analysis.

marisa
Download Presentation

Lecture 12 (parts A & B)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lecture 12(parts A & B) Review: Source transformations Maximum power transfer Derivation of maximum power transfer Thévenin theorem examples Operational Amplifiers Related educational materials: Chapters 4.5, 4.6, 5.1-5.4

  2. Using Source Transformations in Circuit Analysis • Any voltage source in series with a resistance can be modeled as a current source in parallel with the same resistance and vice-versa

  3. Maximum Power Transfer • The load receives the maximum amount of power if RL = RTH • Why?

  4. Maximum Power Transfer – Derivation • Load voltage: • Delivered power:

  5. Maximizing power • Set derivative of power to zero: • Chain rule: • Set numerator to zero:

  6. Maximum Power Delivered • Delivered power: • Letting RL = RTH:

  7. Example 1: Maximum power transfer (a) Determine the load resistance, R, which absorbs the maximum power from the circuit. (b) What is the maximum power delivered to the load?

  8. Example 1(a): Load Design

  9. Example 1(b): Power delivered

  10. Example 2 • Determine the Norton equivalent of the circuit of example 1

  11. Operational Amplifiers • So far, with the exception of our ideal power sources, all the circuit elements we have examined have been passive • Total energy delivered by the circuit to the element is non-negative • We now introduce another class of active devices • Operational Amplifiers (op-amps) • Note: These require an external power supply!

  12. Operational Amplifiers – overview • We will analyze op-amps as a “device” or “black box”, without worrying about their internal circuitry • This may make it appear as if KVL, KCL do not apply to the operational amplifier • Our analysis is based on “rules” for the overall op-amp operation, and not performing a detailed analysis of the internal circuitry • We want to use op-amps to perform operations, not design and build the op-amps themselves

  13. uA741 op-amp schematic • Source: RFIC Technologies web site

  14. Ideal Operational Amplifiers • Typical circuit schematic symbol: • Three-terminal device (2 inputs, 1 output) • Operation characterized by: • Voltage difference between input terminals (vin) • Currents into the input terminals (ip and in)

  15. Ideal Operational Amplifier “Rules” • More complete circuit symbol • (Power supplies shown) • Assumptions: • ip = 0, in = 0 • vin = 0 • V - < vout < V +

  16. Notes on op-amp operation • Output current is generally not known (it is provided by external power supplies) • KCL at input nodes is generally a good starting point in op-amp circuit analysis • vinis multiplied by a large number to get vout • vout is limited by the external power supplies

  17. Op-amp circuit – example 1 • Find Vout

  18. Op-amp circuit – example 2 • Find Vout

More Related