\"Flicker free\" ballasts make use of what to ensure that there is no flicker?

\"Flicker free\" ballasts make use of what to ensure that there is no flicker?

• A. square wave manipulation of the sine wave
• B. Triac dimming
• C. Phase-cut dimming
• D. Constant current

Answer: (A)

Flicker-free operation comes from driving the lamp at a high switching frequency with a waveform that rapidly changes, so the eye can’t perceive any flicker. Electronic ballasts use high-frequency square-wave switching to supply the lamp with pulses that are far above the flicker perception of humans, causing the light output to be effectively averaged over many cycles. By delivering a high-frequency square-wave drive rather than a low-frequency waveform, the lamp’s brightness remains steady even though the current is pulsed. Phase-cut dimming chops the waveform at mains frequency, which can introduce visible flicker unless the system is specifically designed to counter it. Merely enforcing constant current helps keep brightness stable, but it doesn’t by itself eliminate flicker caused by low-frequency modulation.

Flicker-free operation comes from driving the lamp at a high switching frequency with a waveform that rapidly changes, so the eye can’t perceive any flicker. Electronic ballasts use high-frequency square-wave switching to supply the lamp with pulses that are far above the flicker perception of humans, causing the light output to be effectively averaged over many cycles. By delivering a high-frequency square-wave drive rather than a low-frequency waveform, the lamp’s brightness remains steady even though the current is pulsed.

Phase-cut dimming chops the waveform at mains frequency, which can introduce visible flicker unless the system is specifically designed to counter it. Merely enforcing constant current helps keep brightness stable, but it doesn’t by itself eliminate flicker caused by low-frequency modulation.