Zusammenfassung Reaktorphysik
This is a (German) summary of basic nuclear reactor physics that has been written by me during learning for the exam of an university course.
WKB-Näherung
This is a short (German) summary of the WKB approximation applied to the time invariant Schrödinger equation, which is a method used for finding approximate solutions to linear differential equations with spatially varying coefficients.
Fast ballpark calculation of maximum speed for maximum car througput (using simple high-school physics and math)
The fast and short answer to the question which speed would be (under optimal conditions) the speed to choose for maximum car throughput on a single lane. Contrary to the often believed fact it's shown that higher speed does not correlate with higher throughput by using simple high-school math.
Where does complex impedance come from?
This post describes a simple derivation of the complex inpedance formulas well known from electronics.
Capacitance measurement with AVR (simple, fast)
Mini article about the measurement of capacitance with AVRs with a minimum of external components (in it's most extreme form none external components exploiting the gate capacitance of the micro-controllers input)
Z, ABCD, S and T parameters in two port networks
A short summary about the different meaning and interpretation of impedance, ABCD, scattering and transfer parameters in simple (linear) two port networks.
Some Gaussian integrals in 1 dimension
Short summary of various commonly used Gaussian integrals (1 dimensional) most of the time not shown in school textbooks.
Maxwell equation summary
A short summary about the basic properties of Maxwell equations, the resulting electromagnetic wave equations and commonly used gauges (Lorenz, Coulomb).
3D printed parts using PLA and standard FDM process in vacuum?
Just a short description of what I've tried (and didn't expect to work) about the usage of 3D printed parts made out of PLA in the typical desktop FDM 3D printing process, i.e. a method to build really low cost parts at home.
Cutting glass vacuum tubes using hot wire
Something easy and simple. How to cut glass tubes and other glass parts using electrically heated hot wire.
Basic behaviour of thermionic emission cathodes
A short summary about the operation and characteristics of thermionic emission cathodes, the current limiting factors and the most important failure modes
Building a simple improvised electron gun from common of the shelf components
Mini blog article that summarizes the build of a simple 2 mA beam current electron gun from common of the shelf components gathered from the hardware store as well as some 3D printed components.
Summary: Pierce type electron gun essentials and most basic geometry
A short summary about the basic conditions in a pierce type electron gun
Matching impedance using NanoVNA v2, NanoVNASaver and SimSmith
A mini summary on how to perform impedance matching for antennas or other devices using the NanoVNA v2 together with the NanoVNASaver and SimSmith applications based on the impedance matching of an electron deflection system
Composition of atmospheric air and mean thermal speed
Table containing the typical atmospheric air components as well as their mean thermal speed and mean molecular mass.
Ethernet control of Gamma vacuum quad ion pump controller
Notes on the the protocol that's required to remotely control Gamma vacuum ion pumps / titan sublimation pumps via a quad pump controller and some views on the inner workings of my own library implementing the protocol
A vacuum oil well - using water to check for oily contamination in a vacuum chamber
This blog post describes a really simple method to get a hint if the interior of a vacuum chamber has been contaminated with some oil without the use of expensive chemical analysis.
Controlling Pfeiffer Turbopumps using RS485
Pfeiffer makes great turbopumps but sometimes you want to log information or control them from an existing control system. Out of this desire I played around with the RS485 protocol used by Pfeiffer and wrote some simple unofficial tools - that's what this blog entry is about
A simple OpAmp photodiode readout circuit
A short summary on the workings of photodiodes, how one can interface them to simple electronics and a simple amplifier circuit
Building a simple 6 kV DC power supply
Short summary on how to build a small 6 kV power supply using an 2.1 kV microwave oven transformer, two of the accompanying capacitors and a bunch of diodes that is capable of delivering a little bit more than half a kilowatt of power
The capstan equation
A summary on how to derive the capstan equation describing the friction of a rope on a bollard, winch or a capstan
Rendering static two dimensional electric fields caused by point charges using Python
A mini summary on how one can use Python and matplotlib to calculate and render two dimensional static electric fields generated by point charges in infinitly sized space based on Coulombs law and the superposition principle.
Gold plating on copper surfaces
A summary on a procedure on how to use a galvanic process to plate copper (and other metallic surfaces) with gold using a galvanic bath
QR decomposition using Givens rotations
Mini recipe and hopefully descriptive summary on how to perform QR decomposition using Givens rotations which forms the basis of many linear algebra numeric applications such as least squares, GMRES, etc.
Mini summary on how to solve linear equations in Krylov subspaces
A write up of the methods used to iteratively solve arbitrary linear equations systems. This includes the definition of Krylov subspace solvers, the Lanczos and Arnoldi algorithm to build orthogonal subspaces, a summary of the steepest descent and projective methods and then as an real world realization of projective methods the conjugate gradient (CG) and generalized minimal residual (GMRES) method.
Building simple function generators using OpAmps (OpAmp based multivibrator)
Summary on how to use operational amplifiers to build simple function generators such as square wave function generators. This approach can be used to build simple laboratory function generators as well as low frequency oscillators used for various applications.
Logarithm and exponential function with OpAmps
A summary how to implement the logarithmic and exponential function using operational amplifiers - and how to use this to build simple mixers when combining with a simple summation amplifier
