Temperatura de juntura, transistor - Junction Temperature, Transistor - Multisim

[Lepeie]

hi everyone

I have two questions, I do not know if they are linked or are separate questions (I am a new user in multisim and electronic) . First, How I can change the " junction temperature " of a bipolar transistor ?. second , what affects : TNOM T_MEASURED T_ABS in the " junction temperature "?

Thank you so much for everything

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Hola a todos

Tengo dos consultas, que no sé, si están enlazadas o son preguntas separadas (soy un usuario nuevo en multisim y electronica). Primero, ¿Cómo puedo modificar la "temperatura de juntura", de un transistor bipolar?. segundo, ¿en qué afecta las: TNOM T_MEASURED T_ABS, en la "temperatura de juntura" ? 

Muchas gracias por todo

[jcham]

You can set the global operating temperature from the analysis options menu:

This will affect the entire design. Alternatively, you can specify the operating temperature for a specifc BJT by editing it's instance or model properties. If you are using one of the virtual BJTs you can change the TEMP instance parameter from the component properties:

Or you can edit the T_ABS parameter in the model. This will override the global temperature settings. You can do this by editing the model of a BJT:

Hope that helps!

Cheers

Jeff

[Lepeie]

Thank you very much jcham, I modified T_ABS, but have not found any circunstacial change, as it is to change the "junction temperature" carrying electronic circuit (Boylestad - 10th Edition). I will try to "TEMP" (but theoretically have the same values no?). Thank you very very much

What is strange to me, that does not "exist" on a parameter "junction temperature" in some books, called "TJ"

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Thank you so much, from a novice user in electronics and Multisim, I hope your answer, good day!

[jcham]

Varying T_ABS should definitely affect the circuit, how much are you varying it by? If you want to attach the circuit you are working with I can take a look. 

Cheers,

Jeff

[Lepeie]

Thank you very much Jcham, you're very kind. Could I send you a message next Wednesday?.

Have a  good week

Lep

[Buechsenschuetz]

I think the parametersshown in previous posts will only affect simulation of operating temperature or in other words ambient temperature. 

I am not sure whether Multisim can indicate the power dissipated in a transistor (or other semiconductor). If so, you can calculate the junction temperature manually, you also need data about the thermal resistance junction to ambient. These data are usually supplied by the manufacturers. Since this parameter depends on package design, it is probably NOT available in Multisim simulation. 

[jcham]

Yes, in my above responses I assumed you wanted to control the operating temperature to model the effect on simulation. 

Of course if you want to know the physical junction temperature you will see on your device, as Buechsenschuetz said this is dependent on package design and you won't be able to get a direct measurement from Multisim. 

Multisim 14.0 introduced power probes which can be used to measure power dissipated by a component, so you could manually perform the calculation as Buechsenschuetz suggested. 

[Lepeie]

Thank you very much, jcham and Buechsenschuetz.  For your answers and comments. I appreciate you taking my questions. Unfortunately, this weekend I had countless work and finished very sick (cold). So I don't have to send simulations. My apologies for that

I hope you have a good week
regards