Picaxe button help - Electronic Circuits Projects Diagrams Free

colin886 · 1st June 2006, 12:58 AM

On the picaxe pdf (page 25) on the button schematic why do you need a 10k
can't you just skip it?

dknguyen · 1st June 2006, 01:24 AM

Which PDF? I think it is because the PixAxe can only sink/source so much current and the resistor is to limit that current.

EDIT: I think I found the PDF. WIth the 1Kohm resistor right?

Think about it...you connect 5V to 0V through a wire and a switch both of which have essentially zero resistance...how much current do you think flows when the switch is closed? In theory, an infinite amount of current. In practice? As much current as the battery can provide. WIthout the resistor it makes short circuit and that makes stuff overheat, explode and melt.

colin886 · 1st June 2006, 01:27 AM

Sorry forgot link
http://www.rev-ed.co.uk/docs/picaxe_manual3.pdf

dknguyen · 1st June 2006, 01:35 AM

Yeah, without the 10K resistor, when the switch is closed you have a short circuit between 5V and 0V. Remember, a battery isn't just a voltage- it provides a current too and the resistor is there to limit that current.

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1st June 2006, 12:58 AM	(permalink)
colin886	Picaxe button help On the picaxe pdf (page 25) on the button schematic why do you need a 10k can't you just skip it?

1st June 2006, 01:24 AM	(permalink)
dknguyen	Pdf Which PDF? I think it is because the PixAxe can only sink/source so much current and the resistor is to limit that current. EDIT: I think I found the PDF. WIth the 1Kohm resistor right? Think about it...you connect 5V to 0V through a wire and a switch both of which have essentially zero resistance...how much current do you think flows when the switch is closed? In theory, an infinite amount of current. In practice? As much current as the battery can provide. WIthout the resistor it makes short circuit and that makes stuff overheat, explode and melt. Last edited by dknguyen; 1st June 2006 at 01:31 AM.

1st June 2006, 01:27 AM	(permalink)
colin886	Sorry forgot link http://www.rev-ed.co.uk/docs/picaxe_manual3.pdf

1st June 2006, 01:35 AM	(permalink)
dknguyen	CUrretn Yeah, without the 10K resistor, when the switch is closed you have a short circuit between 5V and 0V. Remember, a battery isn't just a voltage- it provides a current too and the resistor is there to limit that current.