## Wire wound variable resistor

What is Wire wound variable resistor?High stability and higher accuracy resistor are always wire wound. It is enclosed in an  insulating cover. Generally Nickel chromium is used because of its very small temperature coefficient of resistance. Wire wound resistor can safely operate at high ...Read More

## Variation of Resistivity with Temperature

What is Variation of Resistivity with Temperature?The resistivity or specific resistance of most material increases linearly wit increase in temperature. At temperature T the resistivity ρT of a material is give by     ΡT=ρ0(1+  α T)   α = ρT-ρ0 / ρ0T Where α ...Read More

## Temperature Co-efficient of Resistance

What is Temperature Co-efficient of Resistance? Consider a conductor having resistance R0 at 00C and RT at T0 C.It is found that normal range of temperature ,the increase in resistance (Rt-R0) is Directly proportional to the initial resistance i-e                         RT-R0α R0 2. It ...Read More

## Effect of Temperature on Resistance

What is effect of temperature on resistance?Resistance of material change with the change in temperature. The effect of temperature on resistance varies according to the type of material (1) Thus the resistance of a pure metal (e.g copper, aluminum )increase with increase of temperature. ...Read More

## what is Conductivity?

What is conductivity? The reciprocal of resistivity of a conductor is called conductivity.It is denoted by the symbol σ. If a conductor has resistivity ρ ,then its conductivity is given by σ. =1/ρ =L/RA The unit of conductivity is mho m-1 or siemen meter ...Read More

## What is EEG?

What is EEG?Electroencephalography, or EEG, is a neurological test that uses an electronic monitoring device to measure and record electrical activity in the brain.Special sensors (electrodes) are attached to your head and hooked by wires to a computer. EEG measures voltage fluctuations resulting from ...Read More

## What is Sag and tension?

What is Sag and tension ?In a overhead transmission line conductor are supported at the towers or at the pole for low voltage transmission lines. The conductor are pulled and string effected. When the conductor are supported in this manner ,it will sag or ...Read More

## ELECTRIC POLARIZATION

What is electric polarization?When insulating material with relative permittivity (or dielectric constant) Eo is inserted into an initially charged parallel plates of a capacitor. Then negative charges appear on the left face and positive charges on the right face of the dielectric  The phenomenon ...Read More

## Capacitor:Capacitance ,symbol

A device which is used for storing electric charges is called capacitor. It consists of two parallel metal plates, separated by small distance. The medium between the two plates is air or a sheet of some insulator. This medium is known as dielectric. When ...Read More

## What is Fuse?Important terms

What is fuse?It is a piece of metal which is inserted in the circuit in series and it will melt when excessive current flows through it and thus breaks the circuit. The fuse clement is generally made of materials having low melting point, high ...Read More