what is a short circuit what is used in an electrical circuit to prevent a short circuit
Tree limbs cause a brusque circuit, triggering an electrical arc during a tempest
A short circuit (sometimes abbreviated to short or s/c) is an electric circuit that allows a electric current to travel along an unintended path with no or very low electric impedance. This results in an excessive current flowing through the circuit. The contrary of a short circuit is an "open circuit", which is an infinite resistance between 2 nodes.
Definition [edit]
A short excursion is an abnormal connection between two nodes of an electrical circuit intended to be at different voltages. This results in an current limited only by the Thévenin equivalent resistance of the rest of the network which can cause excursion damage, overheating, fire or explosion. Although commonly the issue of a fault, there are cases where brusque circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors.
In circuit assay, a short excursion is defined as a connection between two nodes that forces them to be at the aforementioned voltage. In an 'platonic' brusque circuit, this means in that location is no resistance and thus no voltage drop across the connection. In real circuits, the result is a connectedness with almost no resistance. In such a instance, the current is limited but by the resistance of the rest of the circuit.
Examples [edit]
A common type of short circuit occurs when the positive and negative terminals of a battery are connected with a low-resistance usher, like a wire. With a low resistance in the connection, a loftier current will menstruum, causing the delivery of a large corporeality of energy in a short period of time.
A loftier electric current flowing through a bombardment can cause a rapid increase of temperature, potentially resulting in an explosion with the release of hydrogen gas and electrolyte (an acid or a base), which can burn tissue and cause incomprehension or even expiry. Overloaded wires will likewise overheat causing damage to the wire's insulation, or starting a burn down. High current weather may also occur with electric motor loads under stalled weather condition, such as when the impeller of an electrically driven pump is jammed by droppings; this is non a short, though it may take some similar effects.
In electric devices, unintentional short circuits are usually acquired when a wire'due south insulation breaks down, or when some other conducting material is introduced, assuasive charge to catamenia along a dissimilar path than the one intended.
In mains circuits, short circuits may occur between ii phases, between a stage and neutral or betwixt a phase and globe (footing). Such curt circuits are probable to result in a very loftier current and therefore chop-chop trigger an overcurrent protection device. However, it is possible for short circuits to arise between neutral and globe conductors and between two conductors of the same phase. Such short circuits can exist dangerous, particularly equally they may not immediately upshot in a big current and are therefore less likely to exist detected. Possible effects include unexpected energisation of a circuit presumed to be isolated. To assist reduce the negative effects of curt circuits, power distribution transformers are deliberately designed to accept a sure amount of leakage reactance. The leakage reactance (usually almost 5 to 10% of the full load impedance) helps limit both the magnitude and rate of rising of the fault electric current.
A short excursion may atomic number 82 to formation of an electric arc. The arc, a channel of hot ionized plasma, is highly conductive and tin persist even later meaning amounts of original material from the conductors has evaporated. Surface erosion is a typical sign of electric arc harm. Even brusque arcs tin remove significant amounts of material from the electrodes. The temperature of the resulting electrical arc is very high (tens of thousands of degrees), causing the metal on the contact surfaces to melt, pool and migrate with the current, equally well as to escape into the air as fine particulate matter.[ane]
Damage [edit]
A short circuit fault current can, within milliseconds, exist thousands of times larger than the normal operating current of the system.[2] Damage from short circuits can be reduced or prevented by employing fuses, circuit breakers, or other overload protection, which disconnect the power in reaction to excessive current. Overload protection must be chosen according to the current rating of the circuit. Circuits for large dwelling house appliances crave protective devices ready or rated for college currents than lighting circuits. Wire gauges specified in building and electric codes are called to ensure safety operation in conjunction with the overload protection. An overcurrent protection device must be rated to safely interrupt the maximum prospective curt-circuit current.
In an improper installation, the overcurrent from a brusque circuit may cause ohmic heating of the circuit parts with poor electrical conductivity (faulty joints in wiring, faulty contacts in power sockets, or even the site of the short circuit itself). Such overheating is a common cause of fires. An electric arc, if it forms during the short excursion, produces high amount of heat and can crusade ignition of combustible substances as well.
In industrial and utility distribution systems, dynamic forces generated by high brusk-excursion currents cause conductors to spread autonomously. Busbars, cables, and apparatus can be damaged by the forces generated in a short circuit.
[edit]
In electronics, the platonic model (infinite gain) of an operational amplifier is said to produce a virtual brusk excursion between its input terminals because no affair what the output voltage is, the difference of potential betwixt its input terminals is zero. If 1 of the input terminals is connected to the footing, then the other 1 is said to provide a virtual ground because its potential is (ideally) identical to that of the ground.[3] [iv] An platonic operational amplifier also has space input impedance, so unlike a real short circuit, no current flows between the terminals of the virtual short.[5]
Encounter also [edit]
- Annealing past short circuit
- Breaking capacity
- Provisional short-circuit current
- Curt-circuit test
- Other electrical faults:
- Ground fault
- Ohm'south constabulary
- Overcurrent, electrical overload
References [edit]
- ^ "Lab Notation #105 Contact Life - Unsuppressed vs. Suppressed Arcing". Arc Suppression Technologies. April 2011. Archived from the original on September 30, 2018. Retrieved February v, 2012.
- ^ Bhatia, A. "Introduction to Brusk Excursion Analysis" (PDF). PDHonline. sec. What causes a short excursion?. Archived (PDF) from the original on 3 July 2019. Retrieved 3 July 2019.
- Bhatia, A. "Introduction to Short Excursion Analysis". PDHonline (Synopsis).
- ^ Basic Electronics. I. K. International Pvt Ltd. March 2011. pp. 184–. GGKEY:9NLKFQ9D0F2. Archived from the original on 2 May 2013. Retrieved 20 April 2011.
- ^ Robert Spence (5 September 2008). Introductory Circuits. John Wiley and Sons. pp. 99–. ISBN978-0-470-77971-ii. Archived from the original on 2 May 2013. Retrieved 20 April 2011.
- ^ U.A.Bakshi; A.P.Godse (1 Jan 2010). Linear Integrated Circuits. Technical Publications. pp. 4–. ISBN978-81-8431-773-two . Retrieved 20 April 2011.
External links [edit]
- Troubleshooting Strategy for US/Canadian Homes from The Circuit Detective
Source: https://en.wikipedia.org/wiki/Short_circuit
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