Electrical4U 
A toroidal transformer uses a ring-shaped core made from a suitable ferromagnetic material. Line-frequency power units often use wound grain-oriented electrical-steel strip, while higher-frequency designs may use ferrite. Primary and secondary windings pass repeatedly through the centre and are distributed around the core. This closed magnetic path can reduce external magnetic flux when the winding … Read more
Electrical energy is the energy carried by electrons moving from one point to another in a conductor, which makes it a secondary energy source: grids generate it from primary sources such as fossil fuels, nuclear fuel, sunlight, wind and falling water, each converted by its own method. Which source feeds a given grid depends on … Read more
A core-type transformer is defined as a transformer that has a magnetic core with a rectangular shape and two limbs or legs. The core provides a single magnetic circuit for the alternating flux. The windings are cylindrical and concentric, and they are distributed over both limbs of the core. The low voltage (LV) winding is placed near … Read more
A space charge is a non-zero net charge density distributed through a finite volume. It may consist of mobile carriers, fixed ionised dopants or trapped charge in vacuum, plasma, semiconductor or dielectric material. Through Poisson’s equation, this charge changes the electric field, the electric potential and carrier transport. Examples of Space Charge Space-charge regions occur when positive … Read more
Solar power plants generate electricity from sunlight. They fall into two main types: photovoltaic (PV) plants, which convert light directly into electricity using solar cells, and concentrated solar power (CSP) plants, which focus sunlight with mirrors or lenses to heat a fluid that drives a turbine or engine. This page covers the components, layout and … Read more
A heating element is a device that converts electrical energy into heat through the process of Joule heating. When an electric current passes through a resistance, it produces heat. Heating elements are used in various heating equipment or appliances, such as electric furnaces, electric ovens, electric heaters, etc. The performance and life of a heating … Read more
A high-voltage transformer transfers AC power between circuits at different voltage levels through electromagnetic induction. The term has no single worldwide threshold; the rated voltage, insulation level and applicable product standard define the duty. High-voltage transformers include grid power transformers, laboratory test transformers, instrument transformers and converter-duty units. High-voltage design coordinates rated voltage, insulation levels, … Read more
A rheostat is a two-terminal variable resistor placed in series to adjust current. The resulting voltage drops follow Ohm’s law and the rest of the electric circuit. Traditional Rheostats controlled motors, lamps, heaters and laboratory loads, but they dissipate the controlled power as heat. What is a Rheostat? A rheostat varies resistance between a movable … Read more
Photoelectric emission is the release of electrons from a material surface after it absorbs electromagnetic radiation. The emitted particles are photoelectrons. This external photoelectric effect occurs in metals and suitable semiconductor photocathodes. It differs from the internal photovoltaic effect used to separate charge inside a solar cell. What causes photoelectric emission? Quantum theory treats light-matter … Read more
A black body absorbs every bit of electromagnetic radiation falling on it and, in return, emits radiation whose continuous spectrum depends only on its own temperature. That emitted thermal radiation, produced while the body sits in thermodynamic equilibrium with its surroundings, is called black body radiation. Its study underpins work across physics, astronomy and engineering. … Read more