Industrial Electronics

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Industrial Electronics

• IT 332
• Lecture 2
• Thomas E. Scott, PhD

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Overview Power Supply

• AC source for usage as DC (Fig 10.2)
• Sinusoid and RMS (Fig 2.84 and Fig 2.86)
• Plug (Polarized Sec 3.1.3) and wire (Sec 3.1.1)
• Fuse (Fig 3.125)
• Transformer (Fig 3.96)
• Diode Bridge (Diode Fig 4.12) (Bridge Fig
  10.7)
• (Smoothing) Capacitor - Sec 3.6.8 (Fig 10.12)
  Ripple (Fig 3.73)
• Voltage Regulator (Fig 10.4)
• Heat Sink
• Protection Capacitor (Small Transistor
  protection Fig 10.2)
• Protection Capacitor (Large Output Surge
  Suppressor)
• Indicator (LED and Protection resistor) (Fig 5.6
  and Fig 5.10)
• Output wires Wire gage (Table 2.5)

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Power Supply (AC to DC)
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Plug

• Polarity
• Large and small (neutral) prong
• Neutral wire (rough)

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Fuses

• Current limiting device
• For circuit protection
• Circuit breakers are resettable fuses

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WIRE GAGE

• Larger number smaller the wire
• 20 gage smallest practical
• 8 is larger than 12
• 00 is larger than 0
• 000 is larger than 00

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Alternating Current

• Varies with Time
• Magnitude
• Polarity
• Direction of Electron Flow
• Usually Sinusoidal
• Could be Triangular
• Square
• Mixed Mode

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Sinusoidal Waveforms

• Period
• The Amount of Time to Complete One Cycle
• Frequency
• How Many Cycles in a Particular Time
• Usually, cycles per second (hertz)
• Frequency is 1 / period

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Sinusoidal Waveforms
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Sinusoidal Waveforms

• Peak Value (Maximum and Minimum)
• Positive and Negative
• One-Half of Total Voltage or Current Variation
• Peak to Peak
• Total Change in Voltage or Current

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Waveforms

• rms Value
• dc voltage that would produce the same effect
• average power value with time
• Sine Wave
• rms 0.707 x Peak
• Square Wave - rms Peak
• Triangular - rms 0.5 x Peak

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Waveforms

• 110 VAC - rms or Peak ?
• 12 VDC - rms or Peak ?
• Average Voltage - Not Used

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Oersteds Law
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Principles of Electromagnetism

• Electromagnet
• Wrap wires carrying current around
• More wires, Stronger Field (Flux)
• More Current, Stronger Flux
• Fm N x I

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Electromagnetic Devices

• Transformer
• Wires Wrapped Around A Bar
• Primary (Fmp) Np x Ip
• Fmp Fms (Ideal)
• Is Fms / Ns
• Direction (polarity) Related to
• Wire Wrapping Direction
• Current Direction

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Transformers

• Used to
• Isolate electrically one circuit (supply) from
  another
• Used to alter voltage/current magnitude using
  number of turns of wire
• Primary vs Secondary about the same core

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Transformer (VS VP(NS / NP)
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Transformer in Power Supply
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Full Wave Rectification
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Capacitors

• Device for storing electrons(Fig 9-2)
• Composed of separated plates
• Factors affecting
• Area of plate - larger area larger C (Fig 9-6)
• Separation - Field intensity(Fig 9-7)
• closer plates higher intensity
• Dielectric strength
• determines magnitude of intensity at discharge

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Capacitor Materials Section 3.6.5

• Mica - stacked foil or silver mica
• Ceramic - High dielectric constant
• Paper/Plastic - rolled foil
• Electrolytic - foil separated by electrolyte
• Variable - air dielectric
• Trimmers - adjust plate separation

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Applications of Capacitance

• Rectifier (Fig 9-51)
• Tuning
• Computer Memories
• Motor Starters
• Batteries
• Compensation for Inductive Load

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Capacitor Used for filtering
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Voltage Regulation

• Uses Zener Diode Section 4.2.7
• See 10.1.1 and associated summary