1. Components and their operation

3. SMART Funded by The National Science Foundation Diode A diode is an semiconductor component that, in general, will pass current in only one direction

4. SMART Funded by The National Science Foundation Water Analogy of Diodes

5. SMART Funded by The National Science Foundation LED Light-emitting diode Semiconductor Has polarity

6. SMART Funded by The National Science Foundation LED: How It Works

7. SMART Funded by The National Science Foundation Capacitors 1 Store electric charge Consists of two plates of a conducting material separated by a space filled by an insulator Measured in units called farads, F

8. SMART Funded by The National Science Foundation Capacitors 2 Negative lead (-) Electrolytic Mylar Ceramic

9. SMART Funded by The National Science Foundation Capacitor Symbols Fixed capacitorPolarized capacitor Variable capacitor +

10. SMART Funded by The National Science Foundation How to Read Capacitor Value The first two figures give us 10, the third figure gives us 0000, and the letter 10%. We normally express this as 0.1µF.

11. SMART Funded by The National Science Foundation Photoresistors Light sensitive resistors Resistance decreases when light intensity increases Symbol

12. SMART Funded by The National Science Foundation 555 Timer Highly stable devices for generating accurate time delay or oscillation Not programmable Controlled by resistors and capacitors Applications – Pulse generation – PWM – Time delay generation

13. SMART Funded by The National Science Foundation Connection Diagram Identifier

14. SMART Funded by The National Science Foundation Transistor A semiconductor device that acts as – An electrically controlled switch – A current amplifier

15. SMART Funded by The National Science Foundation BJT, JFET, and MOSFET Bipolar Junction Transistor – NPN and PNP Junction Field Effect Transistor Metal Oxide Semiconductor FET BJT transistorMOSFETJFET

16. SMART Funded by The National Science Foundation BJT NPN: a small input current and a positive voltage applied at base allows to flow from collector to emitter PNP: a small output current and a negative voltage at base allows a much larger current to flow from emitter to collector