We know that in induction type energy meters, in order to maintain speed of rotation proportional to power “The phase angle between supply voltage and pressure coil flux should be equal to 90o“. However in actual practice, the angle between supply voltage and pressure coil flux is exactly not 90o but few degrees less. Therefore, some lag adjustment devices are used for adjustment of lag angle. Let us consider the figure given beside:In the beside figure we have introduced another coil which is l

Electrical energy is a fundamental concept in physics and engineering, as well as a practical necessity for everyday life. Electrical energy is the amount of work that can be done by an electric current, or the amount of heat that can be produced by an electric resistance. Electrical energy is also related to electrical power, which is the rate of energy transfer per unit time. In this article, we will explain what electrical energy is, how it is measured, what units are used for it, and how to

Schering Bridge TheoryThis bridge is used to measure to the capacitance of the capacitor, dissipation factor and measurement of relative permittivity. Let us consider the circuit of Schering bridge as shown below:Here, c1 is the unknown capacitance whose value is to be determined with series electrical resistance r1.c2 is a standard capacitor.c4 is a variable capacitor.r3 is a pure resistor (i.e. non inductive in nature).And r4 is a variable non inductive resistor connected in parallel with vari

We have various bridges to measure inductor and thus quality factor, like Hay’s bridge is highly suitable for the measurement of a quality factor greater than 10, Maxwell’s bridge is highly suitable for measuring medium quality factor ranging from 1 to 10, and Anderson bridge can be successfully used to measure inductor ranging from few micro Henry to several Henry. So what is the need for Owen’s Bridge?.The answer to this question is very easy. We need a bridge that can measure the inductor ove

What is Maxwell BridgeA Maxwell Inductance Capacitance Bridge (known as a Maxwell Bridge) is a modified version of a Wheatstone bridge which is used to measure the self-inductance of a circuit. A Maxwell bridge uses the null deflection method (also known as the “bridge method”) to calculate an unknown inductance in a circuit. When the calibrated components are a parallel capacitor and resistor, the bridge is known as a Maxwell-Wien bridge.The working principle is that the positive phase angle of

Anderson’s BridgeLet us understand why there is a need for Anderson’s bridge though we have Maxwell bridge and Hay’s bridge to measure the quality factor of the circuit. The main disadvantage of using Hay’s bridge and Maxwell bridge is that they are unsuitable for measuring the low-quality factor.However, Hay’s bridge and Maxwell bridge are suitable for measuring accurately high and medium quality factors respectively. So, there is need of bridge which can measure low-quality factor and this bri

Before we introduce Kelvin Bridge, it is very essential to know what is the need of this bridge, though we have Wheatstone bridge which is capable of measuring electrical resistance accurately (usually an accuracy of around 0.1%).To understand the need of Kelvin bridge we must first recognize 3 important ways to categorize electrical resistance: High Resistance:Resistance that is greater than 0.1 Mega-ohm. Medium Resistance:Resistance that ranges from 1 ohm to 0.1 Mega-ohm. Low Resistance:Under

Wheatstone BridgeFor measuring accurately any electrical resistance Wheatstone bridge is widely used. There are two known resistors, one variable resistor and one unknown resistor connected in bridge form as shown below. By adjusting the variable resistor the current through the Galvanometer is made zero. When the current through the galvanometer becomes zero, the ratio of two known resistors is exactly equal to the ratio of adjusted value of variable resistance and the value of unknown resistan

Blavier’s Test is used to find the earth fault location in an underground cable. The two ends faulty cable are mentioned as sending end and far end respectively as shown in fig 1. In this test, the sending end of the cable must be open and isolated and the resistance between sending end and earth point is measured by keeping the far end isolated from earth and then it measured keeping far end of the faulty cable, shorted to the ground.Suppose, we get, resistance values R1 and R2 in these two sai

This bridge provide us the most suitable method for comparing the two values of capacitor if we neglect dielectric losses in the bridge circuit. The circuit of De Sauty’s bridge is shown below.Battery is applied between terminals marked as 1 and 4. The arm 1-2 consists of capacitor c1 (whose value is unknown) which carries current i1 as shown, arm 2-4 consists of pure resistor (here pure resistor means we assuming it non inductive in nature), arm 3-4 also consists of pure resistor and arm 4-1 co