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Things and Stuff Wiki - an organically evolving personal wiki knowledge base with a totally on-the-fly taxonomy containing topic outlines, descriptions and breadcrumbs, with links to sites, systems, software, manuals, organisations, people, articles, guides, slides, papers, books, comments, screencasts, webcasts, scratchpads and more. use the Table of Contents to navigate and the Small-ToC / Tiny-TOC header links on longer pages. probably not that mobile friendly atm. i am milk on freenode, give me a pm for feedback, or see About for login and further information. / et / em


See also Physics#Electromagnetism, Hardware, Computing, Living


Ep = mgh Ek = 1/2 mv Eh = cm{delta}T

Lf/v = EH / m

a = V-u / t

v = d/t


Rt (series) = R1 + R2 + R3 ...

Rt (parallel x2) = R1xR2 / R1+R2

Rt (parallel x2+) = 1 / 1/Ra + 1/R2 + 1/R3



  • https://en.wikipedia.org/wiki/Inductance - the property of a conductor by which a change in current flowing through it "induces" (creates) a voltage (electromotive force) in both the conductor itself (self-inductance) and in any nearby conductors (mutual inductance).

  • https://en.wikipedia.org/wiki/Counter-electromotive_force - abbreviated counter EMF or simply CEMF), also known as back electromotive force (or back EMF), is the electromotive force or "voltage" that opposes the change in current which induced it. CEMF is the EMF caused by magnetic induction (see Faraday's law of induction, electromagnetic induction, Lenz's Law).

  • https://en.wikipedia.org/wiki/Biot–Savart_law - an equation describing the magnetic field generated by a stationary electric current. It relates the magnetic field to the magnitude, direction, length, and proximity of the electric current. The Biot–Savart law is fundamental to magnetostatics, playing a similar role to Coulomb's law in electrostatics. When magnetostatics does not apply, the Biot–Savart law should be replaced by Jefimenko's equations. The law is valid in the magnetostatic approximation, and is consistent with both Ampère's circuital law and Gauss's law for magnetism. It is named after Jean-Baptiste Biot and Félix Savart who discovered this relationship in 1820.

  • https://en.wikipedia.org/wiki/Coulomb - a fundamental unit of electrical charge, and is also the SI derived unit of electric charge (symbol: Q or q). It is equal to the charge of approximately 6.241×1018 electrons. Its SI definition is the charge transported by a constant current of one ampere in one second. One coulomb is also the amount of excess charge on a capacitor of one farad charged to a potential difference of one volt.
  • https://en.wikipedia.org/wiki/Ampère's_force_law - In magnetostatics, the force of attraction or repulsion between two current-carrying wires (see first figure below) is often called Ampère's force law. The physical origin of this force is that each wire generates a magnetic field, following the Biot–Savart law, and the other wire experiences a magnetic force as a consequence, following the Lorentz force law.

  • WaveDrom is Free and Open Source online digital timing diagram (waveform) rendering engine that uses javascript, HTML5 and SVG to convert WaveJSON input text description into SVG vector graphics. WaveJSON is an application of the JSON format. The purpose of WaveJSON is to provide a compact exchange format for digital timing diagrams utilized by digital HW / IC engineers.

Electrical engineering

See also Computing, etc.


  • Hackster.io gives professionals and hobbyists the resources they need to build hardware, the easy way.
  • EEVblog Electronics Resource Wiki - This resource site contains useful links and information related to all aspects of Electronics Engineering and associated electronics design.

  • Basic Electronics Tutorials provides students and beginners alike studying Electronics a good Basic Electronics Tutorials and information to help develop a knowledge and understanding of the subject of Electronics.




  • https://en.wikipedia.org/wiki/Transmission_line - a specialized cable or other structure designed to conduct alternating current of radio frequency, that is, currents with a frequency high enough that their wave nature must be taken into account. Transmission lines are used for purposes such as connecting radio transmitters and receivers with their antennas (they are then called feed lines or feeders), distributing cable television signals, trunklines routing calls between telephone switching centres, computer network connections and high speed computer data buses.


  • https://en.wikipedia.org/wiki/Power_inverter - an electronic device or circuitry that changes direct current (DC) to alternating current (AC). The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the DC source. A power inverter can be entirely electronic or may be a combination of mechanical effects (such as a rotary apparatus) and electronic circuitry. Static inverters do not use moving parts in the conversion process.
  • https://en.wikipedia.org/wiki/Rectifier - an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction.


Wire and cable


See also Living#Fuel cell

UPG 12V 55Ah Sealed

  • https://en.wikipedia.org/wiki/Lead–acid_battery - invented in 1859 by French physicist Gaston Planté and is the oldest type of rechargeable battery. Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, its ability to supply high surge currents means that the cells have a relatively large power-to-weight ratio. These features, along with their low cost, make them attractive for use in motor vehicles to provide the high current required by automobile starter motors.

As they are inexpensive compared to newer technologies, lead–acid batteries are widely used even when surge current is not important and other designs could provide higher energy densities. Large-format lead–acid designs are widely used for storage in backup power supplies in cell phone towers, high-availability settings like hospitals, and stand-alone power systems. For these roles, modified versions of the standard cell may be used to improve storage times and reduce maintenance requirements. Gel-cells and absorbed glass-mat batteries are common in these roles, collectively known as VRLA (valve-regulated lead–acid) batteries.

  • https://en.wikipedia.org/wiki/Electric_vehicle_battery - EVB) or traction battery is a battery used to power the propulsion of battery electric vehicles (BEVs). Vehicle batteries are usually a secondary (rechargeable) battery. Traction batteries are used in forklifts, electric golf carts, riding floor scrubbers, electric motorcycles, electric cars, trucks, vans, and other electric vehicles.

Electric-vehicle batteries differ from starting, lighting, and ignition (SLI) batteries because they are designed to give power over sustained periods of time. Deep-cycle batteries are used instead of SLI batteries for these applications. Traction batteries must be designed with a high ampere-hour capacity. Batteries for electric vehicles are characterized by their relatively high power-to-weight ratio, energy-to-weight ratio and energy density; smaller, lighter batteries reduce the weight of the vehicle and improve its performance. Compared to liquid fuels, most current battery technologies have much lower specific energy, and this often impacts the maximal all-electric range of the vehicles. However, metal-air batteries have high specific energy because the cathode is provided by the surrounding oxygen in the air. Rechargeable batteries used in electric vehicles include lead–acid ("flooded", deep-cycle, and VRLA), NiCd, nickel–metal hydride, lithium-ion, Li-ion polymer, and, less commonly, zinc–air and molten-salt batteries. The amount of electricity (i.e. electric charge) stored in batteries is measured in ampere hours or in coulombs, with the total energy often measured in watt hours.



  • https://en.wikibooks.org/wiki/Signals_and_Systems - This book is about the study of engineering signals and systems, from a discipline-neutral approach. It is a fundamental starting point in the field of engineering, and serves as the basic material that other advanced books in the engineering subject area are based. This book looks at the concepts of systems, serving as an introduction to systems theory. Also, this book examines signals, and the way that signals interact with physical systems. While this book strives to be discipline-neutral, it currently is focused strongly on electrical engineering concepts. It is hoped that this book will be expanded to include information from other disciplines as well.


  • https://en.wikipedia.org/wiki/Terminal_(electronics) - the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener. In network analysis, terminal means a point at which connections can be made to a network in theory and does not necessarily refer to any real physical object. In this context, especially in older documents, it is sometimes called a pole.

  • https://en.wikipedia.org/wiki/Electrical_ballast - a device placed in line with the load to limit the amount of current in an electrical circuit. It may be a fixed or variable resistor. Ballasts vary greatly in complexity. They may be as simple as a resistor, inductor or capacitor (or a combination of these) wired in series with the lamp; or as complex as the electronic ballasts used in compact fluorescent lamps and high-intensity discharge lamps.

  • https://en.wikipedia.org/wiki/Capacitor - layers of insulators and conductors. AC will jump the gap because of inductance. smaller caps block lower frequencies because bass frequencies are closer to DC.

  • https://en.wikipedia.org/wiki/Functional_completeness - means that every possible logic gate can be realized as a network of gates of the types prescribed by the set. In particular, all logic gates can be assembled from either only binary NAND gates, or only binary NOR gates.

  • https://en.wikipedia.org/wiki/Semiconductor_device - electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced thermionic devices (vacuum tubes) in most applications. They use electronic conduction in the solid state as opposed to the gaseous state or thermionic emission in a high vacuum. Semiconductor devices are manufactured both as single discrete devices and as integrated circuits (ICs), which consist of a number—from a few (as low as two) to billions—of devices manufactured and interconnected on a single semiconductor substrate, or wafer.

  • https://en.wikipedia.org/wiki/Transistor - a semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.

  • https://en.wikipedia.org/wiki/MOSFET - metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of transistor used for amplifying or switching electronic signals. Although the MOSFET is a four-terminal device with source (S), gate (G), drain (D), and body (B) terminals, the body (or substrate) of the MOSFET is often connected to the source terminal, making it a three-terminal device like other field-effect transistors. Because these two terminals are normally connected to each other (short-circuited) internally, only three terminals appear in electrical diagrams. The MOSFET is by far the most common transistor in both digital and analog circuits, though the bipolar junction transistor was at one time much more common.


Analog electronics



  • https://en.wikipedia.org/wiki/Logic_family - may refer to one of two related concepts. A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compatible logic levels and power supply characteristics within a family. Many logic families were produced as individual components, each containing one or a few related basic logical functions, which could be used as "building-blocks" to create systems or as so-called "glue" to interconnect more complex integrated circuits. A "logic family" may also refer to a set of techniques used to implement logic within VLSI integrated circuits such as central processors, memories, or other complex functions. Some such logic families use static techniques to minimize design complexity. Other such logic families, such as domino logic, use clocked dynamic techniques to minimize size, power consumption and delay.

  • https://en.wikipedia.org/wiki/7400_series - of transistor–transistor logic (TTL) integrated circuits are the most popular family of TTL integrated circuit logic. Quickly replacing diode–transistor logic, it was used to build the mini and mainframe computers of the 1960s and 1970s. Several generations of pin-compatible descendants of the original family have since become de facto standard electronic components.


Integrated circuits

See also Computer#Single-board microcontroller

  • https://en.wikipedia.org/wiki/Programmable_logic_controller - PLC), or programmable controller is an industrial digital computer which has been ruggedised and adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability control and ease of programming and process fault diagnosis.

They were first developed in the automobile industry to provide flexible, ruggedised and easily programmable controllers to replace hard-wired relays and timers. Since then they have been widely adopted as high-reliability automation controllers suitable for harsh environments. A PLC is an example of a "hard" real-time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation will result.

  • https://en.wikipedia.org/wiki/Very-large-scale_integration - the process of creating an integrated circuit by combining thousands of transistors into a single chip. VLSI began in the 1970s when complex semiconductor and communication technologies were being developed. The microprocessor is a VLSI device. Before the introduction of VLSI technology most ICs had a limited set of functions they could perform. An electronic circuit might consist of a CPU, ROM, RAM and other glue logic. VLSI lets IC makers add all of these into one chip.


  • https://en.wikipedia.org/wiki/Electronic_design_automation - a category of software tools for designing electronic systems such as printed circuit boards and integrated circuits. The tools work together in a design flow that chip designers use to design and analyze entire semiconductor chips. EDA is also referred to as electronic computer-aided design (ECAD).
  • https://en.wikipedia.org/wiki/Design_flow_(EDA) - the explicit combination of electronic design automation tools to accomplish the design of an integrated circuit. Moore's law has driven the entire IC implementation RTL to GDSII design flows from one which uses primarily stand-alone synthesis, placement, and routing algorithms to an integrated construction and analysis flows for design closure. The challenges of rising interconnect delay led to a new way of thinking about and integrating design closure tools.

  • Open Collector - carries listings and news for free EDA software and circuit designs. Open Collector supports gEDA.



  • gEDA project has produced and continues working on a full GPL'd suite and toolkit of Electronic Design Automation tools. These tools are used for electrical circuit design, schematic capture, simulation, prototyping, and production. Currently, the gEDA project offers a mature suite of free software applications for electronics design, including schematic capture, attribute management, bill of materials (BOM) generation, netlisting into over 20 netlist formats, analog and digital simulation, and printed circuit board (PCB) layout. The gEDA project was started because of the lack of free EDA tools for POSIX systems with the primary purpose of advancing the state of free hardware or open source hardware. The suite is mainly being developed on the GNU/Linux platform with some development effort going into making sure the tools run on other platforms as well.


  • XCircuit - a UNIX/X11 (and Windows, or Windows using Cygwin and the Cygwin X-Server) program for drawing publishable-quality electrical circuit schematic diagrams and related figures, and produce circuit netlists through schematic capture. XCircuit regards circuits as inherently hierarchical, and writes both hierarchical PostScript output and hierarchical SPICE netlists. Circuit components are saved in and retrieved from libraries which are fully editable. XCircuit does not separate artistic expression from circuit drawing; it maintains flexiblity in style without compromising the power of schematic capture. XCircuit is flexible enough to be used as a generic program for drawing just about anything, and is competitive with powerful programs such as "xfig". It is especially good for any task requiring repeated use of a standard set of graphical objects, including architectural drawing, printed circuit board layouts, and (my personal favorite) music typography (see my Music Page for examples).


  • FreePCB - a free, open-source PCB editor for Microsoft Windows, released under the GNU General Public License. It was designed to be easy to learn and easy to use, yet capable of professional-quality work.


  • KiCad EDA - A Cross Platform and Open Source Electronics Design Automation Suite [8]



  • CircuitBee provides a platform for you to share live versions of your circuit schematics on your websites, blogs or forums.
  • CircuitLab - online schematic editor & circuit simulator
  • upverter - Create hardware better, faster. Design open source and private projects as a team. Draw schematics, layout PCBs and review designs together.



  • Qucs - Quite Universal Circuit Simulator, an integrated circuit simulator which means you are able to setup a circuit with a graphical user interface (GUI) and simulate the large-signal, small-signal and noise behaviour of the circuit. After that simulation has finished you can view the simulation results on a presentation page or window.

  • spicesound - Simulating Analog Audio Cicuits, an extension to ngspice that provides a libsndfile voltage source and the possibility to write ngspice's output in audio-file format. Ngspice is a mixed-level/mixed-signal circuit simulator, based on Berkeley Spice3F5 and developed openly as ngspice sourceforge project. Libsndfile is a C library for reading and writing files containing sampled sound; released in source code format under the GNU Lesser General Public License.


Circuit printers

12/24v system

"Leisure batteries differ in construction from vehicle starter batteries because they are designed for different jobs, and consequently require a different charging regime.

"Fixed voltage battery chargers won't achieve full re-charging of a leisure battery because the lead plates are thicker, so charging has to take place in controlled stages with the voltage level being automatically adjusted throughout to ensure full charge absoprtion. This is where dedicated multi-stage or 'intelligent' chargers need to be used to ensure your battery receives a full, deep charge and its serviceable lifetime is maximised.

"As a rule of the thumb the charger output current should be around 10-15% of your battery's Ah capacity."

  • Capacitor

"you'll find that the spec says you need a BIG electrolytic cap across your battery, you don't need one for a portable system; it is recommended because class D amplifiers can backfeed current. Deep Cycle batteries cope with this; the capacitor is for car setups where the deep cycle battery for the amp is split charged and is only there to run the system full blast for an hour without the engine running."