Electrical4U 
A measurement bridge is an electrical circuit that compares an unknown resistance or impedance with known standards. DC bridges measure resistance. AC bridges balance both magnitude and phase to determine inductance, capacitance or loss. The Wheatstone bridge, Maxwell bridge and Kelvin Bridge all use a null detector, but their connections and error controls differ. A … Read more
As explained in resistance variation with the temperature, the electrical resistance of a material can change when its temperature changes. The size and direction of that change depend on the material and the temperature range. What is the Temperature Coefficient of Resistance? The temperature coefficient of resistance measures changes in the electrical resistance of any … Read more
A magnetic circuit is a closed path that magnetic flux follows, the magnetic analogue of an electric circuit. An iron-cored solenoid carrying DC sets up flux that leaves the N pole, crosses air to the S pole, then returns in the iron. A path that uses both air and iron is a composite magnetic circuit. … Read more
Oscilloscopes, like a multimeter, have finite measurement limits. An oscilloscope result depends on analogue bandwidth, rise time, sample rate, record length, noise, input range and the connected probe system.Analogue bandwidth is normally specified as the frequency at which a sine wave is displayed at 70.7% of its low-frequency amplitude, a reduction of 3 dB. Sample … Read more
An oscilloscope displays a signal against time, making it possible to inspect amplitude, timing, noise and transient behaviour in an electrical field. Its vertical system measures voltage, while its horizontal time base shows when signal events occur. Digital models can calculate many waveform values automatically, but probe choice, scaling, bandwidth, sample rate and grounding still … Read more
What is an Ohmmeter? An ohmmeter, also written as ohm meter, measures electrical resistance. The instrument applies a known test stimulus and measures the response produced by electric current. Micro-ohmmeters and milliohmmeters are designed for very low values, while Megohmmeters, including instruments made by Megger, use higher test voltages to measure insulation resistance. A measured … Read more
The feed water and steam circuit is the water path through a boiler: economizer, drums, water tubes and superheater. Feed is heated, boiled and superheated before it leaves as steam. Economizer The next block of the Feed Water and Steam Circuit is the boiler drum. Boiler Drums Water-tube boilers usually have a steam drum at … Read more
Laplace transformation is an integral transform that maps a time function f(t), defined for t ≥ 0, into an s-domain function F(s). For a linear differential equation with constant coefficients, differentiation becomes multiplication by s, so the ODE becomes algebra. After you solve for F(s), the inverse Laplace transform returns f(t). This page covers the … Read more
Motor thermal overload protection must allow normal starting current but disconnect an induction motor before sustained heating damages its insulation. The principle of three phase induction motor explains why current is high at start. A balanced three phase power supply applied to the stator windings creates a rotating magnetic field at synchronous speed. Conductive rotor … Read more
What is a Nichols Chart? A Nichols chart plots open-loop gain in decibels against open-loop phase in degrees, with closed-loop magnitude and phase contours on the same axes. It is used in signal processing and control system work to read stability margins and closed-loop frequency response. The chart is named after Nathaniel B. Nichols. How … Read more