Electrical4U 
A bimetal is an object composed of two separate metals joined together by a metallurgical process. Unlike alloys, which mix two or more metals into a single substance, bimetals consist of layers of different metals that keep their individual attributes. Bimetallic products or bicomponent materials are other names for the same idea. Bimetals have two … Read more
A planar circuit is a circuit that can be drawn on a flat surface without any wires crossing each other. A non-planar circuit is a circuit that cannot be drawn on a flat surface without wires crossing. The difference decides which analysis tools apply: mesh analysis needs a planar layout, while other methods handle both … Read more
A Johnson counter feeds a shift register’s last-stage inverted output back to the first stage. Other names include twisted ring counter and switch-tail counter. An n-stage design has an intended cycle of 2n states, making it useful for timing sequences and simple decoding rather than ordinary binary-number display. What is a Johnson Counter? A Johnson … Read more
A feeder protection relay protects power system feeders against faults such as short circuits, overloads, ground faults and broken conductors. A feeder is a transmission or distribution line that carries power from a substation to the load or to another substation. When a fault occurs on the feeder, the relay detects it and isolates the … Read more
A monostable multivibrator is a relaxation oscillator that delivers exactly one output pulse of a chosen duration each time an external signal triggers it. It has one stable state and one unstable state, returning to the stable state automatically once the pulse ends. That duration follows from the RC time constant of the circuit, which … Read more
Earth resistance, or resistance to remote earth, describes the power-frequency relationship between an electrode system’s voltage rise and the current flowing from it into the soil. It is also called ground resistance. The value helps engineers assess a grounding system, but it does not by itself establish safe touch voltage, lightning performance or fault clearing. … Read more
A binary number is a number that consists of only two digits: 0 and 1. The binary number system is also known as the base-2 system because each digit represents a power of 2. For example, the binary number 1011 represents 1×2^3 + 0×2^2 + 1×2^1 + 1×2^0, which is equal to 11 in decimal. … Read more
What is a Lamp? A lamp is a source made to produce light. In lighting practice, the word often means a replaceable bulb or tube, while a luminaire is the complete fitting that holds the source, distributes its light and connects it safely to power. Lamps range from heated-filament and gas-discharge sources to modern light-emitting … Read more
What is an Armature? An armature is the winding in which the operating emf is induced in a motor or generator. It carries load alternating or direct current. Its physical location depends on the machine. In a conventional brushed Direct Current machine, the armature winding is usually on the rotor and connects through a commutator. … Read more
What is a Circuit Breaker? A circuit breaker is a switching device that can make, carry and break current in normal conditions and interrupt specified abnormal current in an electrical power system. Its main current path usually has fixed and moving contacts. In many service applications the contacts are normally closed while the protected circuit … Read more