# Application Gallery

The Application Gallery features COMSOL Multiphysics tutorial and demo app files pertinent to the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use tutorial models and demo apps with step-by-step instructions for how to create them yourself. The examples in the gallery serve as a great starting point for your own simulation work.

Use the Quick Search to find tutorials and apps relevant to your area of expertise. Log in or create a COMSOL Access account that is associated with a valid COMSOL license to download the MPH-files.

### Inductance of a Power Inductor

Power inductors are a central part of many low-frequency power applications. They are, for example, used in the switched power supply for the motherboard and all other components in a computer. Computer simulations are necessary in the design of such inductors. This model calculates the inductance from specified material parameters.

### Busbar, AC Analysis

This is a busbar configuration with an AC analysis. The configuration is similar to the introductory tutorial in the book Introduction to COMSOL Multiphysics. However, two conductors are added to represent a more realistic case of magnetic fields surrounding the busbar. The results include Lorentz forces, induced currents, magnetic flux, and temperature.

### Magnetic Signature of a Submarine

A vessel traveling on the surface or under water gives rise to detectable local disturbances in the Earth’s magnetic field. These disturbances can be used to trigger weapon systems. The magnetic signature of a ship can be reduced by generating a counteracting magnetic field of suitable strength and direction based on prior knowledge of the magnetic properties of the vessel. This model ...

### Magnetically Permeable Sphere in a Static Magnetic Field

A sphere of relative permeability greater than unity is exposed to a spatially uniform static background magnetic field. Two formulations are used to solve this problem, and the differences between these are discussed. The field strength inside the sphere is computed and compared against the analytic solution.

### Capacitive Micromotor

This tutorial shows how to model a 2D capacitive micromotor. The motor consists of a rotor and a stator made of polysilicon. The cogs of the stator are subjected to a time-varying pulsed voltage such that the voltage on adjacent cogs vary by a phase difference of 2p/3. As a result, a time-varying torque acts on the rotor thereby rotating it about its center. This model shows how to use an ...

### Tunable MEMS Capacitor

In an electrostatically tunable parallel plate capacitor, the distance between the two plates can be modified by a spring, as the applied voltage changes. For a given voltage difference between the plates, the distance of the two plates can be computed, if the characteristics of the spring are known. Knowledge of this means that the distance between the plates can be tuned via the spring. ...

### An RFID System

RFIDs are used in a multitude of applications such as tracking or identifying consumer products and their packaging. An RFID system consists of two main parts: A tag or transponder with a printed circuit-board (PCB) antenna A reader unit with a larger RF antennaThe reader antenna generates an electromagnetic field that energizes a chip (IC-circuit) inside the tag. The electromagnetic field ...

### Electron Beam Diverging Due to Self Potential

When modeling the propagation of charged particle beams at high currents, the space charge force generated by the beam significantly affects the trajectories of the charged particles. Perturbations to these trajectories, in turn, affect the space charge distribution. The Charged Particle Tracing interface can use an iterative procedure to efficiently compute the strongly coupled particle ...

### Magnetic Damping of Vibrating Conducting Solids

When a conductive solid material moves through a static magnetic field, an eddy current is induced. The current that flows through the conductor, which is itself moving through the magnetic field, induces a Lorentz force back on the solid. Therefore, a conductive solid that is vibrating in a static magnetic field will experience a structural damping. In this example, a cantilever beam is ...

### Electric Shielding Comparison

The electric shielding boundary condition is meant to approximate a thin layer of highly conductive material that provides an additional current path tangential to a boundary. This example compares the electric shielding boundary condition to a full-fidelity model and discusses the range of applicability of this boundary condition.