Industrial Electronics

1
Industrial Electronics

• Lecture 3

2
Silicon

• Valence four with a crystalline structure
• Cubic Crystal
• Essentially a perfect insulator
• Contrast to a metal many free electrons
• Perfect conductor
• Possible to control conductivity

3
Silicon-Controlling Conductivity

• Called Doping
• Arsenic and Antimony N Type
• Rich in Electrons
• Indium, Germanium - P Type
• Electron Deficient (holes)
• Readily accept electrons
• Not positively charged but negatively deficient
• Applications Diodes, Transistors

4
Integrated Circuits

• Silicon is used to build miniature circuits
• Doping accomplished using cylindrical chambers
• Wafer shape shape of cylinder
• Resistors, Capacitors, Transistors

5
Speaker Fig 11-10

• Sound is air movement
• Speaker is cone (paper)
• Rim attached
• Core oscillated
• Oscillation caused by an electromagnet
• Frequency of oscillation produces the sound

6
Oscillators

• Based on the Resistor Capacitor circuit
• RC charge/discharge circuit (Figure 9.6)
• Capacitor accumulates electrons
• Resistor limits the flow of electrons
• Therefore, R adds time limit
• Time Constant
• Sizing R and C produces the time period
• Switch defines charge and discharge
• Produces wave often square wave

7
Astable Multivibrator (Oscillator)

• See Fig 9.7
• RC Based with Transistors (Switch)
• Unstable so runs continuously

8
Integrated Circuit (IC) Oscillator

• Oscillation characteristics determined by the R
  and C of the hook up Fig 9.7
• ON TIME is
• t1 0.693(RaRb)C
• OFF TIME is
• T2 0.693RbC
• Period T TOTAL TIME t1t2
• Frequency 1/T 1.44/(Ra2Rb)C

9
555 IC

• 555 Widely used
• Pulse generator
• Clocks
• Computer
• Triggers for processes

10
Chip Numbering

• Chips (Integrated Circuits) (See Appendix G)
• Number on back describes function
• Dot to indicate pin 1
• Numbering is always counter clockwise starting at
  pin 1
• All (at least, almost all) chips require power
  and ground