# 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?

i've posted this in the arduino forum.. i would like to ask it here as there are lots of pros here too.. hehe..this is the link:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1289980113/0?

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

do tell me if i need to rephrase my question..

Thank you.

-steve0hh

maewert7 years ago

I see that you received answers in the forum but I'll repeat the basic response here.

Input pins are high-impedance inputs, so they will draw very little current (about 1uA).

When configured a outputs, you want to keep the current the pins source/sink to less than 30mA.

As far as reading TTL voltages, a 'low' is below .8 volts, and a 'hi' is above 2 volts.  These are not minimum values on the 'edge', to be sure you'd want to design a low signal to be .5 volts or less and a high to be 2.7 volts or higher so that your circuit is not affected by noise on the input signals.  When the voltage is in between these values, the inputs have hysteresis, so when changing from lo to hi the input signal needs to go above 2.7 volts.  When going from hi to lo the input should go below .5 volts.

(Someone correct me if I misspeak the arduino design!)

Thanks.