Confused...

L

Lez T

Member
Please pardon my ignorance but I am a little confused and am hoping someone will explain the reason for the difference betweem the diagram of how to interface a switch to an input on P25 pf manual 1, and, the diagram of how to interface a switch to an input on P57 pf manual 3. Is there a reason for the extra 1k resistor as I cannot see a reason for it, ( please bear in mind that I am electronicly challenged ). Is the difference for a Digital and an Analogue input?
Thanks.
Lez.
 
M

MartinM57

Moderator
Me too...

You mean page 57 of manual 1 and page 25 of manual 3:)

The 1k resistor is there for safety reasons - if you should accidentally make your PICAXE input pin an output and set it low..then what would happen EDIT: without the resistor in place? At best, you will blow the pin (electrically) and it won't work any more, since you will be connecting (short-circuiting) your 5v power rail to earth.

If you can guarantee never to make your input pin an output, then no resistor is fine.

I would put it in....
 
Last edited:
L

Lez T

Member
Thank you...

@MartinM57
&
@Eclectic

Thank you both, I fully understand the reasoning behind this now, having not ever swapped an input for an output it never even crossed my mind, E as you say belts and braces, works all the time.
Regards.
Lez.

ps Martin you were right with the manual / page numbers.
Apart from being electronicly challenged, I am sometimes lexdixic.
 
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