AC Power Circuit

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AC Power Circuit

• Silicon controlled rectifier
• Pnpn structure
• Anode
• Cathode
• Gate

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SCR Characteristics
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SCR Characteristics

• Curve Tracer
• NPN Transistor Socket
• Anode Collector, Cathode Emitter, Gate Base
• SCR
• Va 20 V
• Ia 20 mA
• Ig/step 0.2 mA
• Steps 10
• Rload 1 k
• Pmax 0.1 W

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Principle

• Gate signal
• in sync
• with a delay
• RC
• Microprocessor control
• http//services.eng.uts.edu.au/venkat/pe_html/ch0
  3s1/ch03s1p1.htm
• http//www.eece.ksu.edu/starret/589/man/F.htmlla
  b

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SCR Circuit to Build

• Use variac and transformer. Do not use function
  generator.

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Anode Waveform
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Gate Waveform
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AC Power Control

• Adjust R1
• 10 k?, 5 k?, 1 k?, 100 ?
• Waveform monitoring
• Resistor load only
• LED brightness
• Wider control range?
• Vary C
• Range of adjustment
• Digital control pulse?

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AC Power Circuits

• SCR and Triac
• Diac
• Optical Coupler

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Applications

• AC power circuits
• Microwave oven
• Light dimmer
• Solid state relay
• http//www.uoguelph.ca/antoon/circ/solidstate.htm
  l
• Industrial equipment
• Motor
• Oven
• Turn on at zero voltage
• Ramp up power with minimum transient

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Activities

• SCR Characteristics
• LED Dimmer
• Waveforms