Electrical4U 
Batteries contain one or more electrochemical cells and provide portable electrical energy. Common consumer cells supply low voltage, but battery chemistry does not determine whether a cell is rechargeable. Standard zinc-manganese dioxide alkaline cells are primary cells and must not be recharged unless the product is specifically marked rechargeable. A Lead-acid battery is a separate … Read more
A nickel-iron battery uses a rechargeable alkaline chemistry with nickel oxyhydroxide positive material and an iron negative electrode. The names Nickel Iron Battery and Edison Battery refer to this system. A Ni-Fe battery is mechanically rugged and can tolerate some electrical abuse, but it is not short-circuit proof and still requires correctly rated protection, charging … Read more
Quantum numbers label the allowed quantum states of electrons in an atom. They describe an orbital’s shell, angular momentum and angular-momentum projection, together with an electron’s spin projection. They do not specify a fixed position or classical path. Electron configurations use four quantum numbers: Principal Quantum Number (n) The principal quantum number, n, labels the … Read more
What Is a Strain Gauge? A bonded resistance strain gauge measures deformation at the surface of a component. Strain is the change in length divided by the original length, so it is dimensionless and is often reported in microstrain. When the component stretches or compresses along the gauge axis, the bonded measuring grid deforms with … Read more
What Are Flexible AC Transmission Systems (FACTS)? FACTS stands for Flexible AC Transmission Systems. IEEE defines the term as AC transmission systems that use power-electronic and other static controllers to improve controllability and power-transfer capability. Depending on the controller, FACTS can regulate voltage, supply or absorb reactive power, change effective line impedance or control power … Read more
A signal is a function that represents information or a measurable quantity. Its independent variable can be time, position or another index. A system can receive signals as inputs and produce signals as outputs.The following basic signal operations transform signal values or the independent-variable axis. Each definition uses a continuous-time signal x(t); the corresponding discrete-time … 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
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
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
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