How to add a specific LED.

im trying to run a simulation on this led with a 19V supply

i am totaly new to the world of electronics. when i go to change the parameters CircuitLab ask for the LED. i have no idea what they are.

here is the led i want to put in:

by a5194326
October 07, 2014

Please see:

You cannot simply map datasheet parameters onto a device simulation model.

However, if you can find a spice model for your target device, then you can edit the relevant parameters of one of the built-in CL models and use that in your circuit.

For more information please see this thread:

Note that there are some unanswered questions about editing CL model parameters (which may not affect you anyway):

This thread has several links to more about spice diode parameters:

So ... what you can do is trawl manufacturers websites for LEDs and then try to find ones with a model.

From there you pilfer the parameters that you can use in the CL model and set up the CL model using them (Edit parameters > Edit individual parameters).

In the background, build a diode test jig like the one in this lively little thread:

(tee hee!) to sanity check your CL LED against its original datasheet.

SPICE parameters for devices have little to do with datasheet specifications. They are much more to do with semiconductor physics and the particular process under which a given device is manufactured at the foundry.

Consequently it is not always a simple task to map datasheet information onto the model parameters.

If you want to try to understand more about what the SPICE - and hence CL - parameters mean in diodes, bipolar transistors and MOSFETs, then you might like to have a look at:

with individual slide sets:

For more detailed information about bjt's in particular, have a look at this book:

available from:


Another excellent (and free) book about transistor modelling, go to:

and register to get a copy of:

Definitive Handbook of Transistor Modeling


by signality
October 07, 2014

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