Re: TI-H: Battery question

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: Battery question
From: pogge@shore.intercom.net
Date: Mon, 25 Aug 1997 09:50:42 -0400
In-Reply-To: <340187c1.286522@pilot.msu.edu>
References: <Pine.SOL.3.95q.970825025937.25049A-100000@y.glue.umd.edu> <Pine.SOL.3.95q.970825025937.25049A-100000@y.glue.umd.edu>
Reply-To: ti-hardware@lists.ticalc.org

At 01:28 PM 8/25/97 GMT, you wrote:
>>what is the VFORWARD turn on voltage?

he said it was 2 volts i think



>All diodes require a certain amount of voltage in order for them to
>properly operate.  Regular diodes have Vf of about 0.7 volts, and LEDs
>generally are around 1.7 to 2.0 volts.  But, once turned on, this
>voltage stays constant and doesn't change.  This is why a resistor is
>required for LEDs, because if you place 6 volts across an LED with a 2
>volt Vf, it will immediately cause the current through the LED to go
>to infinity!  The resistor effectively "eats up" the extra ~4 volts
>and it also limits the amount of current that can flow through the
>LED.  (It's all related to ohms law and kirchoff's voltage laws, and
>the actual equations are quite complicated for a nonlinear device like
>LEDs, but hopefully you get the picture :).
>
>-Mel

ok...well i think he was asking what the Vf was for the particular LED's
the guy was useing, i dont think he wanted to know what Vf meant.

References:

Re: TI-H: Battery question

From: Eric Fiterman <gericho@Glue.umd.edu>

Re: TI-H: Battery question

From: tsaimelv@pilot.msu.edu (Mel Tsai)

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