What is the voltage of a glow-coil?

A glow-coil typically operates at a low voltage, often around 2 volts alternating current (VAC). This low voltage is sufficient to heat the coil to a high temperature, causing it to glow and provide the necessary ignition source for gas-burning appliances like furnaces and boilers. The low voltage ensures safety and compatibility with the ignition systems designed for residential and commercial heating equipment.

Higher voltages seen in other options, like 9VDC or 120VAC, are not suitable for glow-coils as they could lead to excessive heating or even damage to the component. Additionally, 24VDC is often used in control systems, but it doesn't align with the standard operating range for glow-coils. The specific design and application of glow-coils necessitate the use of a low voltage, reinforcing why 2VAC represents the correct choice.