5M10.45 - Light Sensitive Resistors - Negative Feedback

Code Number:
Demo Title:
Light Sensitive Resistors - Negative Feedback
Diode functions
Area of Study:
Electricity & Magnetism
Night light with light sensitive resistor, bulb socket with light sensitive resistor, cord with light sensitive resistor, 7.5 watt light bulbs.

Most of these devices are to be used with low wattage bulbs.  Plug any one of the devices in and cover the resistor hole.  When its completely covered the light should come on to full brightness.  As you let in more ambient light to the resistor the light bulb itself will dim.

  • Paul Chagnon, "Activities With Automatic Night-Lights", TPT, Vol. 35, #1, Jan. 1997, p. 5.
  • Lawrence Ruby and John Hunt, "Investigating the Automatic Night-Light", TPT, Vol. 34, #8, p. 478, Nov. 1996.
  • R. L. T. Wolfson, "Intelligent Light Bulb: A Negative Feedback Demonstration", AJP, Vol. 49, #4, Apr. 1981, p. 374.
  • Don Rathjen, Paul Doherty, "Light Conversation", Square Wheels, 2002, p. 41.
  • Forrest M. Mims III, "Solar-Powered Night Light", Electronic Sensor Circuits & Projects, p. 140.

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