1 / 42

Chapter 2

Chapter 2. RESISTIVE CIRCUIT (cont..). PN SAFIZAN SHAARI PPK MIKROELEKTRONIK. WHEATSTONE BRIDGE. The Wheatstone bridge circuit is used to precisely measure resistance of medium value s, that is in the range of 1 Ω to 1MΩ .

darlington
Download Presentation

Chapter 2

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. Chapter 2 RESISTIVE CIRCUIT (cont..) PN SAFIZAN SHAARI PPK MIKROELEKTRONIK

  2. WHEATSTONE BRIDGE • The Wheatstone bridge circuit is used to precisely measure resistance of medium values, that is in the range of 1Ω to 1MΩ. • The bridge circuit consists of four resistors, a dc voltage source and a detector.

  3. WHEATSTONE BRIDGE • Determine when a bridge is balanced • Determine an unknown resistance with a balanced bridge. Commonly used in conjunction with transducers to measure physical quantities such as strain, temperature, and pressure. Transducers – sense a change in physical parameter and convert that change into an electrical quantity such as a change in resistance.

  4. The Wheatstone bridge circuit:

  5. When the bridge is balanced: • Combining these equation, gives

  6. Solving these equation, yields

  7. DELTA-WYE (PI-TEE) CIRCUIT • If the galvanometer in Wheatstone bridge is replace with its equivalent resistance Rm,

  8. The resistor R1, R2 and Rm (or R3, Rm and Rx) are referred as a delta (∆) interconnection. It also is referred as a pi (π) interconnectionbecause the ∆ can be shaped into a π without disturbing the electrical equivalence of the two configurations.

  9. Delta configuration

  10. The resistors R1, Rm and R3(or R2, Rm and Rx) are referred as a wye (Y) interconnection because it can be shaped to look like the letter Y. The Y configuration also referred as a tee (T) interconnection.

  11. Wye configuration

  12. The ∆ - Y transformation

  13. Using series and parallel simplifications in Δ-connected, yield

  14. Using straightforward algebraic manipulation gives,

  15. The expression for the three Δ-connected resistors as functions of three Y-connected resistors are

  16. Y  transformation Summary: -> Y Y->  Delta

  17. Y  transformation example

  18. Y  transformation example

  19. Example 1 • Find the current and power supplied by the 40V sources in the circuit shown below.

  20. We can find this equivalent resistance easily after replacing either the upper Δ (100, 125, 25Ω) or the lower Δ (40, 25, 37.5Ω) with its equivalent Y. • We choose to replace the upper Δ. Thus,

  21. Substituting the Y-resistor into the circuit,

  22. The equivalent circuit,

  23. Calculate the equivalent resistance,

  24. Simplification of the circuit,

  25. Then, the current and power values are,

  26. Example 2

  27. Find no load value of vo. • Find vo when RL = 150kΩ • How much power is dissipated in the 25kΩ resistor if the load terminals are accidentally short-circuited?

  28. Answer: a) b)

  29. c)

  30. Note that io is the current in the 1.6Ω resistor. • Use current divider to get current in the 6Ω resistor,

  31. Then the power dissipated by the resistor is

  32. Example 4 Find the voltage of vo and vg.

  33. Answer • Equivalent resistance • Current in resistor 30Ω

  34. Voltage v0 • Total voltage at the resistor

  35. Voltage vg

  36. Example 5 Find the current of ig and.io

  37. Answer • Equivalent resistance:

  38. Current values,

  39. Thus,

  40. Example 6 • Determine the value of io

More Related