Variable Resistor
Linear variable resistor.
Description
The Variable Resistor block models a linear variable resistor described by the following equation:
Where:
-
- voltage,
-
- current,
-
- resistance, i.e. the value of the signal on the control port R.
Connections + and - represent electrical ports corresponding to the positive and negative terminals of the resistor, respectively. - The input port of the scalar signal, which sets the value of the resistance. Current is positive if it flows from the positive terminal to the negative terminal, and the voltage across the resistor is equal to the potential difference across the positive and negative terminals, .
The optional H thermal port allows the resistor to be connected to a thermal network. To open the thermal port, select the Enable thermal port checkbox and specify the heat capacity of the resistor using the Thermal mass parameter. You can also specify the initial value of the Temperature variable. The block does not simulate other effects such as temperature-dependent change of resistance.
Ports
R - resistance value signal
scalar
Input port that defines the resistance value.
+ - positive
electricity
Electrical port, represents the positive terminal of a resistor.
- is the negative
electricity
Electrical port, represents the negative terminal of a resistor.
H is a thermal port
heat
A thermal port that determines the temperature of the resistor.
Dependencies
To enable this port, select the Enable thermal port checkbox.
Parameters
Parameters
Minimum resistance R>=0 - minimum allowable resistance
0 (by default) | scalar
Minimum resistance value. If the input signal falls below this level (e.g. becomes negative), this minimum value is used. The parameter value must be non-negative.
Enable thermal port - Enable thermal port
disabled (by default) | enabled
Checking this box displays the H thermal port, which allows the resistor to be connected to the thermal network. Checking this box also enables the Thermal mass parameter and adds the Temperature variable to the Initial Targets section.
Thermal mass is the heat capacity of the resistor
1 J/K (by default) | scalar.
Resistor heat capacity.
Dependencies
To enable this parameter, select the Enable thermal port checkbox.
Initial Targets
Current - initial current value
0 (By default) | scalar
Initial current value.
Voltage - initial value of voltage
0 (By default) | scalar
Initial voltage value.
Temperature - initial value of temperature
300 K (by default) | scalar
Initial temperature value.
Dependencies
To enable this parameter, select the Enable thermal port checkbox.