Electronics for Electricians 7E Unit 02.pptx

ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Unit 2 Power Rating and Heat Sinking Components Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Objectives • After studying this unit the student should be able to: – Discuss why he...

ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Unit 2 Power Rating and Heat Sinking Components Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Objectives • After studying this unit the student should be able to: – Discuss why heat sinks are necessary in electronic circuits – Discuss the use of thermal compound – Explain how thermal compound aids in the transfer of heat from the electronic component to the heat sink Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Power Rating • Measured in watts (w) • Amount of heat the component can dissipate before damage occurs • Formulas: P = E x Iwhere E = voltage, I = current P = I2 x R where R = resistance P = E2/R Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Heat Sinks • Heat sinks – Increase the surface area of the device connected to it • Thermal compound – Ensure a good thermal contact between the device and the heat sink Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Figure 2-3 Uneven surface of an electronic component Figure 2-4 Two components with uneven surfaces joined together Figure 2-5 Heat sink compound used to fill the gaps Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Heat Sinks (cont’d.) Figure 2-6 Heat sinks Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Heat Sinks (cont’d.) Figure 2-7 TO-3 transistor mounted on a heat sink Copyright © 2017 Cengage Learning