View Full Version : Question about RC Decay circuit in Propeller Education Kit

03-12-2012, 06:57 PM
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?


Mike Green
03-13-2012, 02:25 AM
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.

03-13-2012, 06:20 PM
Okay, that makes sense. Thank you.