forward voltage drop option

[kchan]

The vf option on the seven-segment displays are not always visible. How can I enter the vf when it's not available?

[kchan]

help please.

[GarretF]

Hi,

Some more information would be helpful.

1. What are the component's you have selected?
2. What version of Multisim are you running?

If possible, it is also helpful to post your file so I can take a look at it.

[kchan]

I've tried Multisim 10.1 and 11.0 with same results. Attached is the Multisim file with 3 7-segment displays. 2 has the no Vf option and the other does.

[GarretF]

I've tracked it down, and the Vf parameter was removed from the model in 10.1 as the model was removed. This parameter is now built in as part of the model. Please let me know if this is causing particular problems in your case so I can evaluate the new model better.

[kchan]

When the segment starts to flicker, the students would change Vf values, keeping the current limiting resistors the same. It's not a big deal that the Vf option is not there. We just pick a different LED.

[GarretF]

I think you're hitting on part of the reason the option was removed. The option allowed you to modify the display so that its behaviour was inconsistent with reality. You now need to use appropriate current limiting resistors, but if you built the circuit, you would need to do this anyway.

[almica]

I also in need to simulate my high power LED project using XM-L LEDs with following specs:

Vf = 3.0V to 3.1V

If = 1.0A to 1.5A

My project goal is to run the simulation of the LEDs with Vf = 3.08, but I cannot select desired forward voltage. I know this option was available in Multisim 10.0, but I'm runnng 11.0 and don't see forward voltage selection for any current LED modules in 11.0 version.

Can someone help?

Thanks.

[Tien_P]

Hi Almica,

Attached is the LED I copied from the earlier version, you can open the file and build your circuit around it.  

[dagnolof5]

Hi,

How do you open this file in the online version of multisim

Thanks in advance,

Fabrizio