Which statement about high frequency in GTAW is true?

• A. It reduces arc stability.
• B. It provides faster travel speed.
• C. It enables non-contact arc starting.
• D. It is only used with DC power sources.

Answer: (C)

High frequency in GTAW is used to ionize the shielding gas and create a conductive path between the tungsten electrode and the workpiece, allowing the arc to start without touching the workpiece. This non-contact arc starting is the main benefit, letting you ignite the weld cleanly and with precise control.

It also helps keep the arc stable once started, which is especially helpful at the moment of ignition and when welding with alternating current on materials like aluminum. However, it does not make you travel faster—the travel speed is determined mainly by technique, heat input, and filler metal usage. And high frequency is not limited to DC power sources; it can be used with both AC and DC GTAW systems depending on the setup.