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Variable Resistor

Model variable resistor

  • Library:
  • RF Blockset / Circuit Envelope / Elements

  • Variable Resistor block


The Variable Resistor block controls the output of RF Blockset™ feedback circuits using Simulink® controlled resistance in ohms. The minimum value of the resistance (Rmin) is an RF Blockset defined constant independent of the Simulink control signal. The block has two electrical terminals. One terminal is for the Simulink control signal and one terminal is for the RF Blockset signal.



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Simulink control signal, specified as a scalar.

Data Types: double


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Select this parameter, to simulate thermal noise in the variable resistor. Then, in the Configuration block dialog box, also select the Simulate noise check box. By default, both Simulate noise check boxes are selected.

This parameter inserts a current noise source with the single-sided power density of 4 kT/R A2/Hz, where:

  • k is the Boltzmann constant

  • T is the value of the Temperature parameter, in degrees Kelvin. (Also located in the Configuration block.)

Introduced in R2017b