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variable resistor in LTspice?

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fanshuo

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ltspice variable resistor

how to create a variable resistor whose resistance could be changed in an arbitrary way, say sine wave, square wave and etc.


Thanks.
 

taitsoft

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variable resistor ltspice

fanshuo said:
how to create a variable resistor whose resistance could be changed in an arbitrary way, say sine wave, square wave and etc.
Here's an example. Let's say you want a resistor to vary its resistance sinusoidally between 500 ohms and 1500 ohms at a frequency of 1 Hz. All you do is add a resistor to the schematic as you would do normally but instead of specifying the resistor with a fixed value use this function instead:

R=1000+500*SIN(2*PI*TIME)

Look for .PARAM in the help topics for more functions you could try.

David
 

fanshuo

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variable resistor in ltspice

I tried
.param RN=10+sin(400k*pi*time)
and I defined the value of the R1 is RN
the simulation shows warning that
"can't solve .param RN=10+sin(400k*pi*time)"


also I tried to set the resistor value directly as
sin(400k*pi*time)
then it react as"can not find the definition of model sin"


what should I do?
 

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