Differential operators in curvilinear coordinates

We have to use the cylindrical coordinates when the problem is cylindrical symmetry. For example, the eigenmode in a circular waveguide. Althrough there is a general theory for the differential operators in general curvilinear coordinates, it it very difficult to be understanded. There is also the formular for the differential operators in cylindrical coordinates. However … Read more

AD650 Voltage Frequency Converter

The AD650 is a charge balance voltage-to-frequency converter. The input signal is converted into an equivalent current by the input resistance RIN. This current is exactly balanced by an internal feedback current delivered in short, timed bursts from the switched 1 mA internal current source as shown in Fig.1. These bursts of current may be … Read more

Space Charge Limitation

The charges at the cathode reduces the potential that is present in the absence of the electron so that further emission is prevented. The maxium current is said to be the space charge limitation. Child and Langmuir first studied the space charge limitation in 1910s[1,2]. It assumes that two infinite parallel plane electrodes at fixed … Read more

Maxwell’s equation

Maxwell’s equation in vacuum Name Integral equations Differential equations Gauss’s law   Gauss’s law for magnetism Maxwell–Faraday equation(Faraday’s law of induction) Ampère’s circuital law (with Maxwell’s addition) Next, We obtain the electromagnetic wave equation in a vacuum. It is also called Helmholtz equation. Take the Curl of the Faraday equation \(\nabla \times \left(\nabla \times \mathbf {E} \right)=\nabla \times … Read more

Latex examples

Asciimath is a markup language used to write mathematical expressions using plain text. It’s often used in online forums, blogs, and websites where users want to display math equations without using complex mathematical notation. ASCII Math provides a simple and intuitive way to represent mathematical symbols and expressions using standard keyboard characters. Operation symbols Type … Read more

Math tool

Contour plot of the transverse electric mode in a circular cross section wave-guides. Plot real functions for one variable. Plasma tool permittivity Edit tool Latex replace tool Javascript Tool Javascript: export the formular from a form