A voltage dip, also known as a voltage sag, is a temporary reduction in voltage levels in an electrical system. This phenomenon typically lasts for a few milliseconds to a few seconds and can occur due to sudden increases in electrical demand, such as when large machinery starts up or during a fault in the system. Voltage dips can affect the performance of sensitive equipment, leading to malfunctions or shutdowns. They are often measured in percentage drop from the normal voltage level and can be caused by various factors, including power outages, faulty wiring, or overloaded circuits.