Electrical4U 
High Voltage Test (Water Immersion Test) :Type, acceptance and routine tests are the three factory groups. For the water-immersion type test, IS 1554-1 takes about 3 m of core from the finished cable or cord. The core sits in a water bath with the ends at least 200 mm above the water. General-purpose PVC uses … Read more
The annealing test measures elongation at break of annealed copper wires, aluminium welding-cable wires and solid conductors of electric power cables. A current-carrying core of a power cable is twisted and bent during laying, so the metal must stretch without cracking. IS 10810-1 pulls a marked length to fracture and IS 8130 requires that elongation … Read more
Current density is the current through a unit area of a conductor. That quantity is used throughout electrical engineering. Current Density in Metal Imagine a conductor with a cross-section of 2.5 square mm. If an electric potential causes a current of 3 A, the current density is 1.2 A/mm² (3/2.5). This assumes the current is … Read more
An electron volt is the energy one electron gains when it moves through 1 volt. Start from ordinary circuit power: the watt.W = VI, where V is the voltage and I is the current.Current (I) is charge per unit time, so instantaneous power is: Here q(t) is the charge transferred in time t. Energy then … Read more
A small amount of impurity to a semiconductor contributes free electrons or holes and so changes how the semiconductor conducts. That process is doping. A pentavalent donor (atoms with five valence electrons) replaces a host atom. Four valence electrons form bonds with neighbours. The fifth electron is only weakly bound and can become a free … Read more
Conductivity of a semiconductor is set by how many free carriers it has. Metals (conductors) have a high free-electron density and therefore a high conductance (and a low resistance). Insulators have very few free electrons. A semiconductor sits between those two densities, so its conductivity sits between a metal and an insulator. That is why … Read more
Mobility of a charge carrier is the ratio of drift velocity to the applied electric field in a conductor. Drift velocity is set by that field and by the metal’s mobility of charge carriers. Different metals therefore have different drift speeds in the same field.In a metal the valence band is not completely filled, so … Read more
An op amp is extensively used as the main building block of a Digital to Analog Converter (DAC). A DAC is an electronic device in the form of an IC that converts digital signals to equivalent analog signals. DACs can be realized in many ways. One popular DAC circuit is the binary weighted ladder.This DAC … Read more
This test measures insulation and sheath thickness on electric power cables. IS 10810-6 is the Indian method. A power cable needs enough wall to stand the rated voltage and the pull of laying. The product standard then compares the measured average and the measured minimum with its own limits. Apparatus required to test for thickness … Read more
The tensile test measures breaking strength of aluminium wires used in electric power cables. IS 10810-2 pulls a specimen to fracture so the conductor grade can be checked against IS 8130. The metal must survive pulling during stranding and laying. Soft copper uses the annealing (elongation) test instead. Apparatus required for Tensile Test Method of … Read more