What Causes LED Flicker? A Practical Guide to Flicker-Free Lighting

What people call flicker is really temporal light modulation

An LED produces light very quickly in response to electrical current. If the current changes over time, light output can change with it. Those repeated changes in light output are commonly described as flicker; technical literature often uses the broader term temporal light modulation.

Some modulation is slow or deep enough to be visible. Other modulation happens too quickly to be consciously noticed by many viewers, yet it can still be measured with suitable instrumentation. That is why a visual phone-camera test is useful only as a rough screening tool and not a substitute for a proper measurement.

Common causes of flicker in LED lamps

• Insufficient smoothing of rectified mains power in the LED driver.
• Driver control loops that allow large current ripple at twice the mains frequency or at switching frequencies.
• Incompatible wall dimmers, especially when a dimmer was designed for incandescent loads rather than LED electronics.
• Pulse-width modulation (PWM) or other modulation used for dimming, particularly when frequency and modulation depth are poorly chosen.
• A failing driver, loose connection or unstable supply can cause irregular visible flicker and should be investigated rather than ignored.

Why we avoid exaggerated health claims

IEEE 1789 discusses LED modulation frequencies, applications where modulation can pose possible health risks, and recommended practices intended to mitigate known adverse effects. The topic is real, but the response to temporal light modulation varies with frequency, modulation depth, duration, individual sensitivity and the visual task.

For that reason, Pearlexa does not describe a lamp as medically 'strain-free' or claim that one specification can guarantee comfort for every person. A better product claim is that the driver is engineered to minimise visible and low-frequency modulation within its intended operating range, supported by measurement where available.

How to evaluate flicker when buying LED lighting

Start by checking whether the manufacturer publishes measured flicker information or test conditions. If the product is dimmable, ask whether flicker performance remains controlled across the dimming range rather than only at full output.

Also consider compatibility. A smart bulb that performs its own electronic dimming should normally be used on a suitable non-dimmed mains supply unless the manufacturer explicitly states compatibility with a wall dimmer. Putting one electronic control system behind another can create unstable behaviour.

• Prefer products with clear electrical ratings and documented dimming behaviour.
• Do not assume a higher switching frequency automatically means perfect performance; modulation depth matters too.
• Avoid judging flicker solely by slow-motion phone video, because camera exposure and rolling shutter can create or exaggerate bands.
• Use manufacturer support if a lamp shows irregular flicker, especially when the behaviour is new.

Orbit's design goal

Orbit is designed around electronically regulated LED drive rather than allowing the light output to simply follow the AC waveform. The product goal is stable, controllable light across normal operation and app-based dimming.

We are intentionally keeping proprietary driver topology, control-loop implementation and firmware details private. Those are Pearlexa engineering intellectual property. Public technical content focuses on user-visible performance, ratings and testable outcomes.