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Question about RC Decay circuit in Propeller Education Kit — Parallax Forums

Question about RC Decay circuit in Propeller Education Kit

NightbladeNightblade Posts: 8
edited 2012-03-13 11:20 in Learn with BlocklyProp
I am really new to electronics and I have a question about the Figure 7-2 on page 127 of the PEKitLabs-v1.2.pdf book.

It shows that the RC Decay circuit is draining through the resistor. However, since the pin on the microcontroller is in "input" mode, wouldn't some current also be draining through the pin? Or does a pin work something like my multimeter where it is only reading the difference between positive voltage and ground and not actually "consuming" any current?

Thanks
Matt

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2012-03-12 19:25
    When an I/O pin is in input mode, it has a very very high impedance, like a multimeter, on the order of several megaOhms. The amount of current leakage through an input pin is no more than 1uA.
  • NightbladeNightblade Posts: 8
    edited 2012-03-13 11:20
    Okay, that makes sense. Thank you.
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