voltage / resistance = current. simple ohm's law.

E
I R

voltage / current = required resistance


"Bob Liesenfeld" wrote in message
...


bobinphx wrote:

To All, I need to understand a few things about LED's, such as amperage,
current limiting and light output.. Anyone an expert that can explain
things
and answer my further rising questions in terms an electronics hack
(myself)
can understand...

Thanks
Bob in phx...


Well, as a start it is generally assumed that an LED when under
forward bias and lit up has 2V across it with 20mA flowing through it.
This allows you to calculate a series resistor with any applied voltage.
Does this help? Any other questions?

Bob WB0POQ

One issue with calculating the required resistance is that most LED's drop
the voltage about 2 volts.
So if you really wanna be accurate, use:
(supply voltage - 2) / (desired current) = reccommended resistor
But it shouldn't matter too much unless you are either using small voltages
or are concerned about exact current draw.

73
-KG6SGY



"Zombie Wolf" wrote in message
...
voltage / resistance = current. simple ohm's law.

E
I R

voltage / current = required resistance


"Bob Liesenfeld" wrote in message
...


bobinphx wrote:

To All, I need to understand a few things about LED's, such as
amperage,
current limiting and light output.. Anyone an expert that can explain
things
and answer my further rising questions in terms an electronics hack
(myself)
can understand...

Thanks
Bob in phx...


Well, as a start it is generally assumed that an LED when under
forward bias and lit up has 2V across it with 20mA flowing through it.
This allows you to calculate a series resistor with any applied voltage.
Does this help? Any other questions?

Bob WB0POQ

One issue with calculating the required resistance is that most LED's drop
the voltage about 2 volts.
So if you really wanna be accurate, use:
(supply voltage - 2) / (desired current) = reccommended resistor
But it shouldn't matter too much unless you are either using small voltages
or are concerned about exact current draw.

73
-KG6SGY



"Zombie Wolf" wrote in message
...
voltage / resistance = current. simple ohm's law.

E
I R

voltage / current = required resistance


"Bob Liesenfeld" wrote in message
...


bobinphx wrote:

To All, I need to understand a few things about LED's, such as
amperage,
current limiting and light output.. Anyone an expert that can explain
things
and answer my further rising questions in terms an electronics hack
(myself)
can understand...

Thanks
Bob in phx...


Well, as a start it is generally assumed that an LED when under
forward bias and lit up has 2V across it with 20mA flowing through it.
This allows you to calculate a series resistor with any applied voltage.
Does this help? Any other questions?

Bob WB0POQ