BJT Spice Curve Tracer

[BRSHiFi]

Hello,

In spice, what do you need to do to plot the characteristic curves of a BJT? I am using Tina by TI right now and have the attached circuit set up.

What I am attempting to do is sweep the current source on the base and plot the Vce vs. the collector current.

Thanks,
kingneb

 

[Ouroboros]

There are a lot of post-processing options in the paid-for version of TINA to allow various graphs to be drawn of one output versus another. I don't know if they are available in the free version. Have you downloaded the full TINA manuals from the Designsoft website?

 

[Ouroboros]

I see there is some post processing allowed. Look in the 'EDIT' menu after you have done the dc sweep. You can do an X-Y plot of two signals. You would simply do an X-Y plot of Vcc versus Ic.

(reading the full manual is still a good idea though...)

 

[BRSHiFi]

OK, what commands plot voltage vs current? I tried V(Vce) and I(Ic) and it gave me an error.

 

[Ouroboros]

You need to use the 'dc transfer analysis' with 'parameter stepping' of the base current. A single dc transfer curve would show Ic versus Vce for a particular value of Ib.
You don't need the VF1 probe as VF1=VS3.

The context-sensitive help file covers this but can me a bit difficult to find your way around. Open the 'ANALYSIS / MODE' menu to activate parameter stepping. Select 'PARAMETER STEPPING' then click on the HELP button.

The attached pic shows a lower-voltage NPN: Ic versus Vce for 5 values of Ib.

 

[Ouroboros]

BTW, you have your current source the wrong way round!

 

[BRSHiFi]

She is working now.

Thanks.