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LED Lights

Curriculum

  • 1 Section
  • 41 Lessons
  • Lifetime
Expand all sectionsCollapse all sections
  • LED Lights
    41
    • 1.0
      Connect and Blink a Light
    • 1.1
      Script and Tests
    • 1.2
      How it Works
    • 1.3
      On-Off Signals
    • 1.4
      Review and Practice
    • 1.5
      Solutions
    • 1.6
      Set Brightness with a Script
    • 1.7
      Script and Tests
    • 1.8
      How it Works
    • 1.9
      More About A/D
    • 1.10
      Review and Practice
    • 1.11
      Solutions
    • 1.12
      Add a Light
    • 1.13
      Script and Tests
    • 1.14
      How it Works
    • 1.15
      Sequential Blinks
    • 1.16
      Review and Practice
    • 1.17
      Solutions
    • 1.18
      Intro to Lists
    • 1.19
      How it Works
    • 1.20
      Other Data Types in Lists
    • 1.21
      Review and Practice
    • 1.22
      Solutions
    • 1.23
      Blink Sequencing
    • 1.24
      Script and Tests
    • 1.25
      How it Works
    • 1.26
      Zip Lists Together
    • 1.27
      Review and Practice
    • 1.28
      Solutions
    • 1.29
      Measure Blinking Light with a Voltmeter
    • 1.30
      Script and Tests
    • 1.31
      How it Works
    • 1.32
      Change the Resistance
    • 1.33
      Review and Practice
    • 1.34
      Solutions
    • 1.35
      Measure Light with an Oscilloscope
    • 1.36
      Script and Tests
    • 1.37
      How it Works
    • 1.38
      Setting a Trigger
    • 1.39
      Review and Practice
    • 1.40
      Solutions

Change the Resistance

Did You Know: Load or No Load?

In the main activity, you measured the I/O pin high voltage under load.
In the Try This section, you measured the I/O pin high voltage with no load.
In both activities the I/O pin low voltage was not under load because it was trying to supply 0 V to a circuit that had 0 V (GND) at the other end.  No electrical pressure was applied, so no current was flowing through the circuit.  Thus, no current “load” on the I/O pin.

Your Turn: Change the Resistor Value

  • Try replacing the 220 Ω resistor with a 1 kΩ (brown-black-red-gold) resistor.  
  • Repeat the high and low signal I/O pin voltage measurements.  

What I/O pin voltage under load did you observe?  What is your explanation?  

  • Make sure to put the 220 Ω resistor back before moving to the next activity.

 

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