[Help-gnucap] Re: NTC and PTC

[Markus Feldmann]

nbs wrote:
> 2. Above method cannot be used for simulating dynamic thermal effects
> (this is a limitation of Spice) as temperature is constant within a
> simulation sweep. You may want to design your own resistor model where
> temperature will be represented as a signal (for example a node voltage).
> 
> Here is an example of what could be possibly used in hspice:
> 
> i_ntc1 n1 n2 cur='v(n1,n2)/(resistance_value+tc1_param*v(temp_val)'
> v_temperature temp_val 0 pwl (0 0, 1s 10, 3s -10, 4s 0)
> 

Hi,

thanks to your Answer.
I don't understand "dynamic thermal effects".

Does this 2. Method work if i don't sweep the temp, but the current changes?
In my simulation i don't sweep the temp but the current will be raised,
and therefore the resistance of the NTC goes down while the temp of this
NTC is growing up.

Does your circuit above work for me?

Another thing i don't understand your circuit.
I_ntc1 is a current source.
v_temperature is a voltage source but i didn't see nodes.
The cur=... doesn't exist in gnucap.

mfg Markus