Shin Chin LEDs

You shouldn't use LEDs with a fixed voltage. The datasheet says 20 mA is safe:

For maximum current, e.g. for pulsed applications, maybe you have to ask the manufacturer.

snipped-for-privacy@frank-buss.dehttp://www.frank-buss.de,http://www.it4-systems.de

It maybe silly, but this is the first need I have had to work with LEDs. Apparently the idea is to use a resistor to set the required current from the supply voltage.

Thanks,

Fred

Yes, usually a resistor is sufficient. If you have a regulated fixed voltage, which could be higher than the forward voltage, try different resistors until you'll get the desired current. Usually I use half of the specified current, because modern LEDs are too bright anyway and with half the current they live longer.

If you have multiple LEDs and you really want the exact same brigthness, you can use a constant current source:

snipped-for-privacy@frank-buss.dehttp://www.frank-buss.de,http://www.it4-systems.de

Yep, that's about what I was thinking.

Thanks for the confirmation.

Fred

try Rseries = Vsupply - Vled /.020

Steve