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How do you simulate a variable resistor in LTspice?
Try LTspice – Making a Variable Resistor
- Prepare voltage source V1 and set the node voltage.
- The voltage value of the voltage source V1 is assumed to be the resistance value.
- Set the value of resistor R1 to R = V(VR).
- Run the simulation by applying voltage source V2 (here, 5V) to the Tran analysis setup and resistance.
What is variable resistor use for?
Variable resistors are widely used in electric circuits to adjust the value of current or voltage, since the resistance of variable resistors can be set to a certain value. Variable resistors allow you to adjust the value of voltage by changing the resistance and keeping current constant .
What is the symbol for a variable resistor?
A variable resistor also called an adjustable resistor, consists of two terminals, where one of the terminals is a sliding or moving contact often known as a wiper. The variable resistor IEC symbol is represented by a rectangular box and an arrow across (or above) it, like that shown in the figure below.
Is a rheostat a resistor?
Rheostat, adjustable resistor used in applications that require the adjustment of current or the varying of resistance in an electric circuit. The rheostat can adjust generator characteristics, dim lights, and start or control the speed of motors.
What is another name for a variable resistor?
potentiometer
When a variable resistor is used as a potential divider by using 3 terminals it is called a potentiometer. When only two terminals are used, it functions as a variable resistance and is called a rheostat.
What are the two examples of variable resistor?
Some examples of variable resistors are the volume control knob on a radio and a dimmer switch used for a light. Rheostats and potentiometers are two common types of these devices.
How does a variable resistor work?
A variable resistor works by adjusting the path that current has to flow. The dial you turn will move another piece of wire inside the resistor. The end result is that the electricity will travel through a certain length of the strip depending on where you turn the knob.
Why does a rheostat have 3 terminals?
A 3 terminal pot used with 3 terminals, is basically just a voltage divider. As you move the wiper, you increase one resistor in the voltage divider, while decreasing the resistance in the other.
What is the difference between a resistor and a rheostat?
As nouns the difference between resistor and rheostat is that resistor is one who resists, especially a person who fights against an occupying army while rheostat is an electrical resistor, with two terminals, whose resistance is continuously variable by moving a knob or slider.
How to do a LTspice resistor simulation?
Create a text filename XLOAD.SUB into your LTSPICE/LIB/SUB directory, with the following contents (the “v1” line is long, not broken): The simple .asc simulation with the symbol I made, and the plot planes showing current and supply rippled voltage below. Note that based on the PWL timmings, xLoad starts running at 100ms and finished at 235ms.
How to change the value of a resistor?
If you want to step through values for resistor values (example R): Set the value of resistor that you want to be variable, to be {R} (don’t forget the curly brackets!) If you want to sweep the value of R in time, then it’s not possible as the simulators will have convergence problems!
How to change the resistance of a varistor?
Unfortunately using a varistor will not work, as a varistor itself has a dependence on the voltage across it. Much simpler is to right click onto an existing resistor, and to enter a formula. E.g. will linearily reduce the resistance from 11Ohm to 1Ohm over the time of 100ms.