Voltage spike

In <a href="/facts/Electrical_engineering/YYXW1KLW">electrical engineering</a>, spikes are fast, short duration electrical <a href="/facts/Transient_(electricity)/mzrDXMvd">transients</a> in voltage (voltage spikes), current (current spikes), or transferred energy (energy spikes) in an electrical circuit.
Fast, short duration electrical transients (<a href="/facts/Overvoltage/LsVwLvVQ">overvoltages</a>) in the <a href="/facts/Electric_potential/Nmqm6hm5">electric potential</a> of a <a href="/facts/Electrical_network/zt94kTW0">circuit</a> are typically caused by

<ul><li><a href="/facts/Lightning/dLTuxz8n">Lightning</a> strikes</li>
<li><a href="/facts/Power_outage/CBp7xY9w">Power outages</a></li>
<li>Tripped <a href="/facts/Circuit_breaker/vbw6cWSe">circuit breakers</a></li>
<li><a href="/facts/Short_circuit/r09vaaeQ">Short circuits</a></li>
<li>Power transitions in other large equipment on the same power line</li>
<li>Malfunctions caused by the power company</li>
<li><a href="/facts/Electromagnetic_pulse/fBXSm3Hf">Electromagnetic pulses</a> (EMP) with <a href="/facts/Electromagnetism/oAkmALHT">electromagnetic</a> energy distributed typically up to the 100 kHz and 1 MHz frequency range.</li>
<li><a href="/facts/Inductance/oIxj7JxX">Inductive</a> spikes</li></ul>
In the design of critical infrastructure and military hardware, one concern is of pulses produced by <a href="/facts/Nuclear_explosion/BtpfgcUg">nuclear explosions</a>, whose nuclear electromagnetic pulses distribute large energies in frequencies from 1 kHz into the <a href="/facts/Gigahertz/6Wshj5qm">gigahertz</a> range through the atmosphere.
The effect of a voltage spike is to produce a corresponding increase in <a href="/facts/Electric_current/Dc1xdnUX">current</a> (current spike). However some voltage spikes may be created by current sources. Voltage would increase as necessary so that a constant current will flow. Current from a discharging <a href="/facts/Inductor/YnfAXB3x">inductor</a> is one example.
For sensitive <a href="/facts/Electronics/E4JhgISq">electronics</a>, excessive current can flow if this voltage spike exceeds a material's <a href="/facts/Electrical_breakdown/btrl0FPI">breakdown</a> voltage, or if it causes <a href="/facts/Avalanche_breakdown/PD2E9dPy">avalanche breakdown</a>. In <a href="/facts/Semiconductor/zFf3mGTE">semiconductor</a> <a href="/facts/P-n_junction/CaKIdLPg">junctions</a>, excessive electric current may destroy or severely weaken that device. An <a href="/facts/Avalanche_diode/y7J5DvAq">avalanche diode</a>, <a href="/facts/Transient_voltage_suppression_diode/3DG9FK2C">transient voltage suppression diode</a>, <a href="/facts/Varistor/UwUQT2Dk">varistor</a>, overvoltage <a href="/facts/Crowbar_(circuit)/zkTmPxkS">crowbar</a>, or a range of other <a href="/facts/Overvoltage/LsVwLvVQ">overvoltage</a> protective devices can divert (<a href="/facts/Shunt_(electrical)/EEBIeEdo">shunt</a>) this transient current thereby minimizing voltage.
Voltage spikes, also known as surges, may be created by a rapid buildup or decay of a magnetic field, which may <a href="/facts/Electromagnetic_induction/T36JjtgY">induce</a> energy into the associated circuit. However voltage spikes can also have more mundane causes such as a fault in a <a href="/facts/Transformer/EYYfXWrF">transformer</a> or higher-voltage (primary circuit) power wires falling onto lower-voltage (secondary circuit) power wires as a result of accident or storm damage.
Voltage spikes may be longitudinal (common) mode or metallic (normal or differential) mode. Some equipment damage from surges and spikes can be prevented by use of <a href="/facts/Surge_protector/o3LqlVNv">surge protection</a> equipment. Each type of spike requires selective use of protective equipment. For example, a <a href="/facts/Common-mode_signal/8GCxkDAb">common mode</a> voltage spike may not even be detected by a protector installed for normal mode transients.
Power increases or decreases which last multiple cycles are called swells or sags, respectively. An uninterrupted voltage increase that lasts more than a minute is called an overvoltage. These are usually caused by malfunctions of the <a href="/facts/Electric_power_distribution/F5NfTeWP">electric power distribution</a> system.

Voltage spike open-in-new

Voltage spike