A short circuit, also known as a 'short,' is a dangerous low-resistance path across a voltage source that can lead to significant heating effects, potential damage or fires.
Too little resistance can cause a short circuit, which can create an unintended path for the flow of current. A short circuit is an undesired low-resistance connection across a voltage source, often caused by worn insulation allowing two wires to come into contact. When a short circuit occurs, the resistance r can be very small, leading to high power dissipation according to the formula P = V²/r, where P denotes power, V is the voltage, and r is the resistance. The power dissipation can result in excessive thermal energy, potentially causing materials to melt or ignite. Furthermore, an increase in temperature due to a short may decrease the resistance even further due to ionization, which can lead to a dangerous cycle of increasing power and ionization, especially in high-voltage scenarios.