In monopolar electrosurgery, which statement describes the frequency change at the active electrode?

• A. From high frequency to low frequency at the active electrode
• B. The frequency remains constant across the circuit
• C. Low frequency from wall source to high frequency at active electrode
• D. There is no frequency change

Answer: (C)

High-frequency energy is required in monopolar electrosurgery to avoid nerve and muscle stimulation while producing controlled tissue heating. The power comes from the wall at about 50/60 Hz (low frequency), but the electrosurgical unit converts it to a high-frequency current—typically in the hundreds of kilohertz—before it reaches the active electrode. So the frequency indeed changes from low at the wall source to high at the active electrode. This high-frequency delivery allows effective cutting or coagulation with minimal unintended muscular response, which wouldn't occur if the energy remained at a low frequency.