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Physics thermoelectricity related plot

Posted 9 years ago

Why, I cannot see the plot when I type of the following code:

In[56]:= << PhysicalConstants` (* tick mark used, next to number 1 \
key*)

In[57]:= BoltzmannConstant
Out[57]= (1.38065*10^-23 Joule)/Kelvin

In[58]:= Vt[T_] := BoltzmannConstant*T/ElectronCharge
In[111]:= Vt[1]

Out[111]= (0.0000861734 Joule)/(Coulomb Kelvin)
In[60]:= Ies = 10^-9 (*  Unita A Transistor reverse current *)

 Ic[Vbe_, T_] := Ies*(Exp[Vbe/(Vt[T])] - 1)
In[116]:= Plot[Ic[Vbe, 273], {Vbe, 0, 0.7}]
POSTED BY: David Rod
2 Replies
Posted 9 years ago

You might edit in a little note saying what version of Mathematica you are using. The way units were handled was completely changed starting with version 9 and examples for a version you don't have won't be helpful.

If you are using version 9 or later then you might compare this with what you showed. And watch for the missing _ in your Ic definition.

In[1]:= boltz = UnitConvert[Quantity["BoltzmannConstant"], "Joules"/"Kelvins"]

Out[1]= Quantity[1.38065*10^-23, ("Joules")/("Kelvins")]

In[2]:= echarge = UnitConvert[Quantity["ElectronCharge"], "Coulombs"]

Out[2]= Quantity[1.6021766*10^-19, "Coulombs"]

In[3]:= Vt[T_] := boltz*T/echarge

In[4]:= Vt[1]

Out[4]= Quantity[0.000086173, ("Joules")/("Coulombs" "Kelvins")]

In[5]:= Ies = 10^-9 (*Unita A Transistor reverse current*)

Out[5]= 1/1000000000

In[6]:= Ic[Vbe_, T_] := Ies*(Exp[Vbe/QuantityMagnitude[Vt[T]]] - 1)

In[7]:= Ic[Vbe, 273]

Out[7]= (-1 + E^(42.5074 Vbe))/1000000000

In[8]:= Plot[Ic[Vbe, 273], {Vbe, 0, 0.7}]

Vbe plot

If you insert PlotRange->All just before the final closing ] of that Plot then you will be able to see the current out to 0.7 volts.

Please check this carefully and point out any mistakes that you see. Thank you

POSTED BY: Bill Simpson

Please edit your TITLE and make it meaningful and describing your question.

Please read the rules of this forum - especially about code formatting - then edit your post and format code properly.

POSTED BY: Moderation Team
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