Hello,

I am new here and did search the forums about simulating a potentiometer already. But I did not find an answer....

My problem: I have a very simple circuit: A 12V voltage, a 120ohm resistor and in row a 120ohm poti down to mass. Very simple is'nt it...

The poti is to measue the liquid level in a tank amd I whant to simulate the circuit (and additions I whant to make later) if the value of the poti is changing rapidly. The only simlution I found was simulationg the poti with the step command. But that does not give me an dynamic behavior of the circuit but only two or more static values.

So, does anyone has an idea?

Greatins, Stephan

 

hi StA,
Welcome to AAC.
Do you have an LTSpice asc file to post?
E

 

Sure. What you need is a voltage controlled potentiometer. The wiper position is controlled by a voltage. That way it can change as fast as you want. Can such a thing be implemented? It is possible but I have not had any occasion to work out the details.

 

Hm, who can help me to get a voltage controlled viper. I am a beginner.....

 

Here's a simple voltage-controlled potentiometer consisting of R1 and R2.
Rpot is the total resistance. The wiper position goes from minimum to maximum as the control voltage (wiper) goes from 0 to 1V.

The '1m' in the R value is to ensure the resistance is never zero, which LTspice would complain about.

 

Hm, who can help me to get a voltage controlled viper. I am a beginner.....

Hello, I found this link for a variable resistor from a voltage source: I haven't tested it yet but it makes some sense.
https://redgardenengineering.com/wp-content/uploads/2014/09/RG00056-BRF-A01.pdf
Hope this helps
Alex

 

That linked method is unnecessarily involved. Any resistor in LTspice is inherently programmable by simply right-clicking its symbol and setting its value with R= ......

 

You can also use "time" as a variable to control the resistor voltage.