what is shunt resistance

A shunt resistance is a device that creates a low-resistance path for an electrical current in a circuit. It is used in various applications such as bypassing defective devices in Christmas lights, managing unwanted short circuits in photovoltaics, and protecting equipment from lightning strikes. Shunt resistors are also used to measure electric current, both alternating and direct, by measuring the voltage drop across the resistor. A shunt resistor is connected in parallel with an ammeter to extend its range, and it is also connected in series with the load whose current is to be measured. The shunt resistor has a maximum current rating, and the resistance value is given by the voltage drop at the maximum current rating. Shunt resistors are commonly made up of a material having a low-temperature coefficient of resistance, giving it a very low resistance over a wide temperature range. In solar cells, low shunt resistance causes power losses by providing an alternate current path for the light-generated current, which reduces the amount of current flowing through the solar cell junction and reduces the voltage from the solar cell.