# Physics

### Zusammenfassung Reaktorphysik

04 Aug 2014 - tsp

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-NÃ¤herung

01 Feb 2014 - tsp

This is a short (German) summary of the WKB approximation applied to the time invariant SchrÃ¶dinger 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)

25 Apr 2019 - tsp

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?

08 Aug 2024 - tsp

This post describes a simple derivation of the complex inpedance formulas well known from electronics.

### Topology basics

08 Aug 2024 - tsp

Basic definitions for topology (notes taken during various lectures)

### k-Means clustering algorithm

22 Mar 2020 - tsp

Short summary about the k-means algorithm and it's usage

### Capacitance measurement with AVR (simple, fast)

09 Jul 2020 - tsp

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

12 Jul 2020 - tsp

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

11 Sep 2020 - tsp

Short summary of various commonly used Gaussian integrals (1 dimensional) most of the time not shown in school textbooks.

### Maxwell equation summary

22 Sep 2020 - tsp

A short summary about the basic properties of Maxwell equations, the resulting electromagnetic wave equations and commonly used gauges (Lorenz, Coulomb).

28 Sep 2020 - tsp

### 3D printed parts using PLA and standard FDM process in vacuum?

13 Jan 2021 - tsp

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

02 Mar 2021 - tsp

Something easy and simple. How to cut glass tubes and other glass parts using electrically heated hot wire.

### Basic behaviour of thermionic emission cathodes

28 Apr 2021 - tsp

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

28 Apr 2021 - tsp

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

12 May 2021 - tsp

A short summary about the basic conditions in a pierce type electron gun

### Short Kalman filter summary

19 May 2021 - tsp

A short summary about Kalman filtering

### Matching impedance using NanoVNA v2, NanoVNASaver and SimSmith

03 Jun 2021 - tsp

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

02 Jul 2021 - tsp

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

17 Aug 2021 - tsp

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

01 Sep 2021 - tsp

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

29 Oct 2021 - tsp

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

30 Oct 2021 - tsp

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

01 Nov 2021 - tsp

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

15 Nov 2021 - tsp

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

27 Nov 2021 - tsp

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

12 Dec 2021 - tsp

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

08 Dec 2021 - tsp

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

- tsp

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)

24 Jan 2022 - tsp

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.

### PID control loop in a nutshell

22 Feb 2022 - tsp

Short dive into the basics of PID loops

### Logarithm and exponential function with OpAmps

27 Feb 2022 - tsp

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

### Controlling the Korad KA3005P using Python

15 Jul 2022 - tsp

A short summary on how to control the Korad KA3005P power supply using Python as well as some simple samples on how to use my own control library

### OpAmp based voltage controllable current source

19 Aug 2022 - tsp

A simple temperature drift compensated voltage controlled current source up to 8A (10A peak) and 30V rail to rail based on OPA549 or other power operational amplifiers

### Measuring the speed of light at Wiener Forschungsfest 2022

12 Sep 2022 - tsp

This article allows you to discover how we (a group from TU Vienna and University of Vienna) brought the fascinating world of physics to life at the Wiener Forschungsfest 2022! Using a visible range laser, a bicycle wheel, and modern photodiodes, we demonstrated how to measure the speed of light in an interactive and engaging setup designed mainly for children. This hands-on experiment highlighted the incredible speed of light while also conveying the fact that light is fast but not infinitly fast and allowed visitors to influence the accuracy of the measurement themselves. This article provides a short summary about the historical context, experimental setup, and the exciting outcomes of this educational outreach project.

### Heterodyne, Superheterodyne, Homodyne and Lock-In Amplifier

21 Dec 2022 - tsp

A mini introduction about the terms heterodyne, superheterodyne, homodyne and lock-in amplifier

### Detecting frequency, delay and phase relation as well as multiple targets using correlation functions

29 Dec 2022 - tsp

A short story about how one can use autocorrelation and cross-correlation functions on discretized samples of radio frequency data and also noise to detect the frequency of a single signal, the delay of a reflected signal, the phase relation between two signals and how one can track multiple reflective targets in applications like LIDAR, sonar or radar using correlations - and how to get them robust against external influence.

### A mini recipe to fit arbitrary models to data using lmfit in Python

11 Jan 2024 - tsp

In this blog post, we navigate through an unorthodox yet effective method of building models using the lmfit library, a wrapper around scipy's fitting routines. The article dives into a hands-on approach for fitting noisy data with a custom-defined Gaussian model, while suggesting that the conventional wisdom of lmfit isn't the only path to success. The tutorial initializes by installing lmfit and swiftly moves to crafting a function for the Gaussian model, which involves defining an objective function to decipher the best parameters for data fit. It guides the reader through generating synthetic noisy data, plotting it for visual aid, and conducting the fitting process. Through this procedure, a parameters are constructed and optimized to fit our model to the noisy data, followed by a presentation of the fitting report. Finally, the results are visualized, and the article concludes by discussing the advantages of this method, especially when dealing with complex or iterative models. The full code for the exercise is accessible in a GitHub GIST, allowing readers to directly engage with the material covered.

### Electric dipole interaction of atoms with radiated electromagnetic waves

16 Feb 2024 - tsp

A short summary on the interaction of alkali atoms with electromagnetic radiation

Dipl.-Ing. Thomas Spielauer, Wien (webcomplains389t48957@tspi.at)

This webpage is also available via TOR at http://rh6v563nt2dnxd5h2vhhqkudmyvjaevgiv77c62xflas52d5omtkxuid.onion/