Re: TI-H: Battery question


[Prev][Next][Index][Thread]

Re: TI-H: Battery question



>what is the VFORWARD turn on voltage?


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
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The TI-Memory Expansion Homepage
-http://www.egr.msu.edu/~tsaimelv/expander.htm


Follow-Ups: References: