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Showing posts from September 11, 2016

Electromagnetism Basics

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From wikipedia Quantities and unitsElectromagnetic units are part of a system of electrical units based primarily upon the magnetic properties of electric currents, the fundamental SI unit being the ampere. The units are: ampere (electric current)coulomb (electric charge)farad (capacitance)henry (inductance)ohm (resistance)siemens (conductance)tesla (magnetic flux density)volt (electric potential)watt (power)weber (magnetic flux) In the electromagnetic cgs system, electric current is a fundamental quantity defined via Ampère's law and takes the permeability as a dimensionless quantity (relative permeability) whose value in a vacuum is unity. As a consequence, the square of the speed of light appears explicitly in some of the equations interrelating quantities in this system. SI electromagnetism units
vte Symbol[4]Name of QuantityDerived UnitsUnitBase UnitsIelectric currentampere (SI base unit)AA (= W/V = C/s)Qelectric chargecoulombC

Brief information about joule thief.

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Reference From Wikipedia.
Joule thief From Wikipedia, the free encyclopedia
A generic, conventional joule thief, shows components and how they are connected. This example uses a redLED. A ferritetoroid is wound to form a coil with primary (white) and feedback (green) windings. A 2N2222Atransistorand 1000 ohmresistor are used. A joule thief is a minimalistArmstrong[1] self-oscillating voltage booster that is small, low-cost, and easy to build, typically used for driving small loads. This circuit is also known by other names such as joule ringer or blocking oscillator. It can use nearly all of the energy in a single-cell electric battery, even far below the voltage where other circuits consider the battery fully discharged (or "dead"); hence the name, which suggests the notion that the circuit is stealing energy or "joules" from the source. The term is a pun on the expression "jewel thief": one who steals jewelry or gemstones. The circuit is a variant of t…

Making and learning about inverter

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Operating Principle of an Inverter An inverter can be taken as a crude form of UPS. Obviously the main use of an inverter is only for powering common electrical appliances like lights and fans during a power failure. As the name suggests the basic function of an inverter is to invert an input direct voltage (12VDC) into a much larger magnitude of alternating voltage (generally 110VAC or 220VAC).
Before learning how to build an inverter, let’s first understand the following fundamental elements of an inverter and its operating principle: Oscillator: An oscillator converts the input DC (Direct Current) from a lead acid battery into an oscillating current or a square wave which is fed to the secondary winding of a power transformer. In the present circuit, IC 4049 has been used for the oscillator section. Transformer: Here the applied oscillating voltage is stepped up as per the ratio of the windings of the transformer and an AC much higher than the input DC source becomes available at the…