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Electronics – Learning Outcomes
 Explain the role of a diode.
 Compare the current required for an LED to that for a
bulb.
 Set up simple circuits with switches, buzzers, LEDs, and
resistors.
 Measure the resistance of an LDR under varying light
conditions.
 Identify applications of the diode.
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Explain the Role of a Diode
 Recall that current flows from the positive terminal of a
battery to the negative terminal.
 A diode is a device that allows current to flow in one
direction only. The arrow points the direction that current
can flow.
 In which circuit will the bulb light?
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Compare Currents for LED and Bulb
 LEDs require less current than bulbs.
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Set Up Circuits – Buzzers
 Like this:
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Set Up Circuits – Light Emitting Diodes
 Like this:
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Measure Resistance of a LightDependent Resistor
 Set up the circuit diagram
shown.
 Measure resistance under
varying light levels.
 Note lower resistance under
higher light levels and higher
resistance under low light levels.
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Identify Applications of a Diode
 Most electronics have diodes in them as they are useful
in turning a.c. to d.c.
 LEDs are used in displays, torches, room lights etc.
 LDRs are used in streetlights to make them only turn on
when it gets dark.