Which control adjusts the frequency in GTAW?

• A. Pre-Flow Control
• B. High Frequency Control
• C. Arc Length Control
• D. Post-Flow Control

Answer: (B)

In GTAW, keeping the arc stable and easy to start relies on the high-frequency circuit that ionizes the shielding gas to initiate and sustain the arc. The control that adjusts how fast that high-frequency signal oscillates—the frequency knob—is the High Frequency Control. Increasing the frequency makes the oscillation rate higher, which improves arc starting and stability, especially at low amperage or on AC welding. A higher frequency tends to produce a more focused arc with less wandering, while a lower frequency can make the arc feel less stable. The other controls manage gas flow timing and the physical gap between the electrode and work: pre-flow and post-flow control the shielding gas delivered before and after the arc, and arc length control adjusts the distance. They don’t change the oscillator frequency, which is why the High Frequency Control is the correct one.