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Author Topic: Ohm's Law  (Read 562 times)

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Offline rahulpwnsTopic starter

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Ohm's Law
« on: November 19, 2011, 08:07:53 PM »
hey,
i need help with calculating the amount of ohms my resistors need to be with ohm's law.
i have a sensor that has an Operating voltage of 5v and a max current of 25mA.
would i do 5v/.025A?

-rahulpwns

Offline Soeren

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Re: Ohm's Law
« Reply #1 on: November 19, 2011, 08:51:05 PM »
hey,
i need help with calculating the amount of ohms my resistors need to be with ohm's law.
i have a sensor that has an Operating voltage of 5v and a max current of 25mA.
would i do 5v/.025A?

-rahulpwns

Since you don't like using Google to get your answers, let us do your footwork and direct you towards this calculator combining Ohms Law and Watts Law ;)
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Gertlex

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Re: Ohm's Law
« Reply #2 on: November 19, 2011, 08:51:39 PM »
That would indeed give you a value of Ohms, but the rest of us have no idea what sensor you're using, and therefor whether what you're doing makes sense...
I

Offline rahulpwnsTopic starter

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Re: Ohm's Law
« Reply #3 on: November 19, 2011, 11:53:13 PM »
sorry if i came across as too vague.
@soren i have been researching the formula, but i have not come across a site which has helped me understand what values of current to use.
here is the link to the sensor:
http://www.pololu.com/catalog/product/959

Offline bens

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Re: Ohm's Law
« Reply #4 on: November 20, 2011, 12:02:58 AM »
Hello.

That sensor already has a current-limiting resistor for the IR LED built-in.  You do not need an external resistor to use it.

- Ben

 


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