Common questions about TP-Link Smart Wi-Fi Dimmer

Configuration Guide
Updated 09-18-2023 02:39:51 AM 34803
This Article Applies to: 

Q1: What types of bulbs are compatible with the Smart Dimmer and what is the maximum power?

A: Bulbs can be categorized by dimming type as Incandescent/Halogen, Magnetic Low-voltage (MLV), Electronic Low-voltage (ELV), Neon/Cold Cathode (Magnetic Ballast), Fluorescent (Electronic Fluorescent Dimming Ballast), and Light Emitting Diode (LED) (Electronic LED Driver).

Our Smart Wi-Fi Dimmer is compatible with Incandescent/Halogen, Magnetic Low-voltage (MLV), LED based on TRIAC Phase Cut(Leading Edge Dimming), refer to the below table:

Product Model

Supported Bulb Types

Dimming Type


Dimmable LED (MLV) - 150W Max
Incandescent - 300W Max

Leading Edge Dimming / TRIAC Phase Cut




Tapo S500D(US)

Tapo S505D(US)1.6/TS25(US)1.6



Note: It’s suggested to contact the bulb’s Support to check the supported dimming type of the bulb.

Refer to the below link for more about TRIAC Dimmer & Dimming:


1. The dimming performance can vary significantly between different types of light bulbs and even between brands and models, so we cannot 100% guarantee all dimmable bulbs are compatible with our smart dimmer. Some LED bulbs, for example, require specific dimmers designed for LED technology. When using TRIAC phase-cut dimmers, it's crucial to check compatibility and ensure that the bulb and dimmer are rated to work together.

2. Not all LED bulbs are designed to be dimmable. LED bulb manufacturers typically mark bulb packaging with an icon and label it as dimmable if it has been designed to work with dimming. If your LED bulb flickers, pulses, buzzes or has a limited dimming range, it likely was not designed for dimming and should be replaced with another suitable model.

Q2: What are the possible phenomena if my bulb and dimmer are not compatible?

A: The incompatibility between bulb drivers and smart dimmers can cause a host of problems. Seven such problems are:

  1. Flickering: The bulb may flicker or flash on and off when the dimmer is adjusted.
  2. Inconsistent dimming: The dimmer may not smoothly adjust the brightness of the bulb. Instead, the brightness levels may jump or fluctuate unpredictably when the dimmer is adjusted.
  3. Dead travel: This occurs when changing the dimmer setting produces no visible shift in the light level.
  4. Audible noise: Due to electrical interference or voltage fluctuations.
  5. Drop-out: The bulb shuts off completely as it is dimmed.
  6. Ghosting: Where light is still visible when the dimmer switch is fully off.
  7. Overheating: Incompatible dimmers can sometimes cause the bulb to overheat. This can be a fire hazard and can also significantly reduce the lifespan of the bulb

Q3: Why I can turn on/off the bulb via the dimmer, but cannot adjust the brightness of the light?

A: 1. Check the dimmer type of the bulb and its power to exclude the incompatible problem.

Our Smart Wi-Fi Dimmer is compatible with Incandescent/Halogen, Magnetic Low-voltage (MLV), and LED based on TRIAC Phase Cut(Leading Edge Dimming). While it doesn’t support lamps based on PWM(pulse width module) or ELV(electronic low voltage)dimming.

2. Ensure that the wiring is correctly installed and connected according to the User guide.

3. If you have ruled out compatibility and wiring issues, it is possible that either the dimmer or the bulb itself is defective. Try testing with an Incandescent/Halogen bulb to see if the problem persists.

Q4: Why do my bulbs flicker within a certain dimming range?
A: 1. Poor-quality or incompatible bulbs may exhibit flickering, especially when dimmed. Refer to the Q1 to check if the bulb's dimmer type is compatible with the dimmer. It may be necessary to try different bulb brands or models to find ones that work well with your dimmer.

2. If you use smart dimmer to control several bulbs in a series, it is suggested to use the bulbs of the same model from the same brand. You could also reduce the bulb's number and suggest controlling only one dimmer bulb at the same time to have a try.

3. Check whether the house circuit power supply is stable, and other unstable electrical devices in the same environment.
4. Use the Diming Calibration function to test whether the bulb is normal within a certain brightness range? If yes, it is an incompatible problem, it’s suggested to dim within this normal brightness range.

Q5: Why do my LED make buzzing sound within a certain dimming range?
A: Since TRIAC dimmer (TRIAC Phase Cut) works by changing the cyclic current sent to the LED to dim the brightness, bulb’s electronic component will make noise during a sudden increase in current. The higher the load power, the higher the noise.

We recommend that you reduce the bulb power or limit the dimming range until the noise is within your acceptable range. If you still cannot accept it, it is suggested to purchase another ELV dimmer but may cost more.

Q6: What’s Dimming Calibration?

A: All bulbs vary and some bulbs switch off when dimmed below moderate levels. Dimming calibration lets you set the lowest possible brightness for your bulbs to ensure you get the best possible dimming experience and avoid issues such as flickering, uneven dimming, or limited dimming range.

Refer to the link for more information: What is Dimming Calibration and how it works?

Q7: Whether smart bulb can work with my smart dimmer or not?

A: No, smart bulb cannot not work with smart dimmer, which may cause damage to the bulb or the circuit.

Our Kasa/Tapo bulbs have built-in dimming capabilities and can be controlled using Kasa/Tapo App, voice assistants(like Amazon Alexa or Google Assistant).

You can also use smart button(such as S200B) or smart action to realize the smart control of the bulb. (Please don't turn off the power when using the smart bulb)

More information about Tapo/Kasa bulb:

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