# Hello everyone. i need some help on arduino

hello everyone,
as you can see… this is my first post on this forum… i’m still a noob and is trying to learn this stuff… i’ve been reading through this forum and looking through the spec sheets on the Arduino website.

i’ve some questions to ask you guys as im afraid i’ll burn out my Arduino board.

1. If i configure my Arduino Digital pins and analog pins to INPUT. what is the maximum voltage and current i can supply the pins…
( I know that the VOLTAGE must be less then 5 v <correct me if i’m wrong> ) but i don’t know about the maximum current that i can supply to the pins

2. What are the voltage and current for the pins to register a HIGH or LOW?
i know that if LOW< 3volts > HIGH … (correct me if im wrong again) but what about the current?

My English is not very good, i hope you guys understand what i’m trying to ask…

Thank you.

-steve0hh

UPDATE:
My problem solved… thanks guys! =)

You don't really supply current to a pin, it takes what it wants. In the case of a uC input that's such a small amount as to not normally something that matters. You could connect the IP directly to a 100A 5v supply and it would still only take about .00000000000000002 A

Same answer for the second question, if the voltage is there it will work. Don't worry about current.

You're right about the voltages. Stay within the power rails and the threshold can be considered to be around 3v although it's actually closer to 1v (.2 of VCC).

Rob

That's a bit low, actually the input leakage current is 1uA that is 0.000001 A But still insignificant ;)

What the poster might be asking is how much current can you TAKE OUT of a pin. In that case I would say 35mA should be the maximum. So you have to do things to limit the current to this or below. At 40mA damage starts being caused.

Graynomad You don't really supply current to a pin, it takes what it wants. In the case of a uC input that's such a small amount as to not normally something that matters. You could connect the IP directly to a 100A 5v supply and it would still only take about .00000000000000002 A

Same answer for the second question, if the voltage is there it will work. Don't worry about current.

You're right about the voltages. Stay within the power rails and the threshold can be considered to be around 3v although it's actually closer to 1v (.2 of VCC).

Yes.. I get it now.. Thank you..

Grumpy_Mike That's a bit low, actually the input leakage current is 1uA that is 0.000001 A But still insignificant

What the poster might be asking is how much current can you TAKE OUT of a pin. In that case I would say 35mA should be the maximum. So you have to do things to limit the current to this or below. At 40mA damage starts being caused.

Err, Yes.. I've knew about the maximum current i can draw from a single I/O pin,30mA.. just that i thought that if i supply a high current like example "1A" i would burn out the I/O pin while reading it,like a LED.. haha.. silly me.. =)