Electrical4U 
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
Fan-out in digital electronics is the number of same-family gate inputs that one logic-gate output can drive without leaving the valid logic levels. One output can feed several inputs, but only up to that count.The limit is set by how much current the output can source at a high level and how much current it … Read more
Error detection and correction codes add extra bits so a receiver can see whether a digital word was changed in transit, and in some codes restore the original bits. Analog and digital links both pick up errors; a computer or a comms link needs a definite check because one wrong bit can change a code. … 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
Armature reaction is the armature mmf acting on the main field. At no load the magnetic neutral axis sits on the geometrical neutral axis, so the brushes sit there too. On load the armature flux lies along the interpolar axis and looks roughly triangular. That brush-axis mmf cross-magnetizes the main field. Flux crowds at the … Read more
What is a Signal Generator? Signal generators provide controlled electrical stimuli for design, verification, repair and troubleshooting. Depending on the instrument, the output may be periodic, pulsed, modulated, patterned or an arbitrary stored waveform. Typical settings include frequency, amplitude, DC offset, phase, duty cycle, sweep, burst and modulation. A generator supplies the stimulus; an oscilloscope, … Read more
A digital frequency meter, also called a frequency counter, measures the repetition rate of a periodic electrical signal and displays the result in hertz. A direct counter counts input cycles or pulse edges during a precisely timed gate interval. It then divides that count by the gate time. The number of displayed digits is not … 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 Oscillator Transducer? An oscillator transducer is a type of transducer in which a measured quantity changes an oscillator’s frequency. Force, pressure or displacement can move a mechanical element that changes capacitance or inductance. The system then measures frequency and uses a calibration relationship to recover the input quantity. It does not inherently … 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