1 / 25

Understanding Resistors: Types, Ratings, and Connections in Electronics

This chapter focuses on various aspects of resistors, essential components in electronic circuits. It covers types of resistors including wire-wound, carbon composition, and film-type resistors, highlighting their construction and applications. The section also explains resistor ratings, tolerance, and wattage, which dictate their usage in circuits. Detailed insights into series and parallel resistor connections are provided, including calculations for total resistance using specific formulas. The chapter concludes with practical exercises and preparation for lab work, emphasizing the importance of resistors in electronics.

ksena
Télécharger la présentation

Understanding Resistors: Types, Ratings, and Connections in Electronics

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. EET 110 - Electronics Survey Chapter 10 - Resistors

  2. Resistors • Resistor Wire • Nichrome wire used for heating - I2 R • high resistance results in a voltage drop • Resistors • made from a variety of materials • The lead pencil resistor

  3. Resistors • Ratings of resistors • RESISTANCE • determined by markings • TOLERANCE • determined by marking • WATTAGE RATING • determined by size or marked

  4. Types of resistors • Wire-wound resistors • usually larger, power resistors • Carbon Composition resistors • a cylindrical shaped block a carbon compound • Film type resistors • a layer of resistive material on an insulated rod • Both Carbon Composition and film type resistors are embedded in a cylindrical package.

  5. Types of resistors • Resistor networks • a number of resistors packaged together as group of identical resistors. • Precision resistors • usually +/- 1% • Adjustable resistors • changeable after the circuit is constructed - trimmer or variable types

  6. Rheostats & Potentiometers • Potentiometers • a POT • variable resistor with three terminals • each end of a resistive path and a wiper • Rotary or slide pot • Trimmer • screw variable • Taper • may be linear or non-linear (logarithmic)

  7. Resistor Color Code • consists of 4 bands of color • 1st & 2nd band give value • 3rd gives multiplier • 4th (if present) gives tolerance

  8. Resistor Color Code • Black 0 1 • Brown 1 10 • Red 2 100 • Orange 3 1000 • Yellow 4 10000 • Green 5 100000 • Blue 6 1000000 • Violet 7 10000000 • Gray 8 • White 9

  9. Resistance is read by taking the color code • And applying the color code • here RED = 2, VIOLET = 7, BROWN = x10 • gives 270 ohms • GOLD = +/- 5%

  10. Color Code Mnemonic • Bugs Bunny Raids Our Young Garden, But Violets Grow Wildly • Black Brown Red, Orange, Yellow, Green, Blue, Violet, Gray, White

  11. Precision Resistors • 1 % and 2% tolerance resistors must have THREE significant digits of value • Brown, Black, Black, Black, Brown • 100 x 1 w/ Brown = +/- 1% tolerance

  12. Size gives wattage 1/8 watt 1/4 watt 1/2 watt 1 watt 2 watt

  13. Series connection of resistors • Resistors connected in series result in added resistance 100 ohm Rtotal = 100 + 500 + 1000 ------ 1600 ohms 500 ohm 1000 ohms

  14. Series resistors • Voltage is distributed across the resistors

  15. The voltage across each resistor in series is a proportion of the resistance to the total 1k Here each resistor is 1/3 of the total, so the 9 volts is distributed across the three resistors evenly - 3 volts each +9V 1k 1k

  16. Series Resistors • Resistors in Series have an equivalent total resistance equal to the algebraic sum of each resistance. • The voltage across any one resistor is series is given by the ‘Voltage Divider Rule’ VT = R i/RT x VT (page 108) • see example 10-2

  17. Parallel connection • In Parallel resistors, the INVERSE of the total is equal to the total of the inverses of each resistor in parallel. 1/Rt = 1/R1 + 1/R2 + 1/R3 1/Rt = 3/150 = 1/50 Rt = 50 ohms 150 150 150

  18. To find the total resistance of two unequal resistors in parallel - use the formula

  19. For example if a 60 ohm and 40 ohm resistor are connected in parallel, the total resistance is given as RT = (60 x 40)/(60 + 40) = 2400/100 = 24 ohms

  20. Parallel Resistors • To find the total resistance of resistors in parallel

  21. Series - Parallel Connection • If combinations of resistors are connected in series and parallel, a total can be derived, by alternately simplifying with the series / parallel formulas • See example 10-7

  22. Two resistors in parallel, in series with a third

  23. First solve for the parallel combination • RT(parallel) = (30 x 60)/(30 + 60) = 20 ohms • This leaves an equivalent

  24. These two resistances in series gives • RT = 40 + 20 = 60 ohms total

  25. Homework • Do Problems – Ch9: 1&2, Ch10: 1-6 • Prepare for lab (ohm readings) • Read Chapters 11 & 12

More Related