November 2, 2015 at 16:03LED Dimming
To adjust the brightness of incandescent lamps, a dimmer was invented a long time ago - a simple electronic device that changes the brightness of the lamp due to the "cutting" part of the sinusoid of the mains voltage.
The incandescent lamp is simple, and the LED lamp contains a complex electronic circuit, so with dimming everything is not easy there. Today I will tell you what dimmers do, how they differ among themselves, and how dimmable LED lamps behave compared to incandescent lamps when adjusting brightness.
Let's start with what dimmers do. Here is a voltage waveform.
The dimmer "cuts off" a piece of a sinusoid. At half brightness, “halves” of the sinusoid remain in each half-cycle.
At a minimum brightness level, only small “tails” remain.
In fact, the dimmer switches the load on and off 100 times per second and the brightness depends on the moment of switching on.
All dimmers with a two-wire connection cannot “open” completely - for operation they need power, which they receive due to the small voltage remaining when the “opening” is incomplete. At maximum brightness, the waveform at the dimmer output looks like this.
When turned on via a dimmer, ordinary LED lamps will turn on at full brightness from a certain moment of regulation or blink when trying to dim. Dimmable LED lamps allow you to adjust the brightness, which contain a special circuit that recognizes dimming and controls the lamp stabilizer circuit.
When dimming, LED bulbs behave differently from incandescent bulbs. When the incandescent lamp burns very weakly, the LED lamp still glows quite brightly. This is how the lamps look, connected via the same dimmer at minimum brightness.
All dimmers have a different minimum level. For example, in one of the Chinese dimmers, the waveform at the minimum level looked like this.
At the same time, LED dimmable lamps glowed quite brightly.
For dimming LED lamps, it is important that the minimum level of adjustment is as low as possible. If the filament of the incandescent lamp at the minimum level of adjustment glows a little dark red, such a dimmer is suitable for LED lamps, if the filament of the filament lamp is yellow, the LED lamps at the minimum dimming level will shine too brightly.
I connected the incandescent lamp to the three dimmers I have and measured the True RMS output voltage with a multimeter.
The black Chinese dimmer on the wire is 98 V. The
IKEA
dimmer is 66 V. The Chinese dimmer with a shiny handle is 46 V. The
maximum level for all dimmers is also different:
On the network is 228 V. The
black Chinese dimmer on the wire is 211 V. The
IKEA dimmer is 221 V.
Chinese dimmer with shiny handle - 220 V.
Dimmable LED lamps differ in the minimum level of dimming. Some allow you to reduce the brightness to 5%, and some only up to 20%. Here, for example, the Navigator NLL-C37-5-230-2.7K-E14-FR-DIMM and IKEA 102.667.54 lamps, included in the same dimmer at a minimum brightness level.
Another problem when dimming LED lamps is sound. Almost all dimmable lamps quietly itch when dimming, but some lamps with some dimmers begin to hum quite loudly. The dimmer itself can itch.
Another problem is the incompatibility of dimmers with LED lamps. Some dimmers "go crazy" when LED bulbs are turned on. I have a Univex switch in my room with dimming and remote control. When LED lamps are screwed into the chandelier, the light turns off immediately after being turned on. Replacing one of the six lamps with a conventional incandescent lamp helped. Now there are five LED lamps and one incandescent lamp in the chandelier and the switch works correctly.
The last problem is the incompatibility of the lamps and the dimmer. However, some LED lamps may not turn on or turn on once. For example, of the six lamps in the chandelier, when turned on, only five or four can be lit, and when turned on again, all six will be lit. The reason most likely is the interference introduced by the dimmer. For a Chinese black dimmer at half brightness, the output waveform looks like this:
It is possible that the interference pulse affects the operation of the lamp electronics.
Conclusions:
1. All dimmers have different minimum levels. LED lamps need to be as low as possible;
2. The maximum level is also different. If it is not high enough, the lamps will never burn at full brightness;
3. All dimmable LED lamps have a different level of minimum dimming;
4. Incompatibility of the lamp model with the dimmer model is possible;
5. When dimming, the lamps may hum, when changing the dimmer, the hum may decrease.
ps That's how I spend my day off. :)
pps Details have appeared on lamptest.ru for financial support of the project, in addition, now you can order testing of any lamp from any online store.
upd .: In addition to simple dimmers that cut off the leading edge of the sine wave (leading edge), there are dimmers that cut off the trailing edge and PWM dimmers. I have not seen such yet. Thanks to Ilya Savinkin for the tip.
© 2015, Alexey Nadezhin
The incandescent lamp is simple, and the LED lamp contains a complex electronic circuit, so with dimming everything is not easy there. Today I will tell you what dimmers do, how they differ among themselves, and how dimmable LED lamps behave compared to incandescent lamps when adjusting brightness.
Let's start with what dimmers do. Here is a voltage waveform.
The dimmer "cuts off" a piece of a sinusoid. At half brightness, “halves” of the sinusoid remain in each half-cycle.
At a minimum brightness level, only small “tails” remain.
In fact, the dimmer switches the load on and off 100 times per second and the brightness depends on the moment of switching on.
All dimmers with a two-wire connection cannot “open” completely - for operation they need power, which they receive due to the small voltage remaining when the “opening” is incomplete. At maximum brightness, the waveform at the dimmer output looks like this.
When turned on via a dimmer, ordinary LED lamps will turn on at full brightness from a certain moment of regulation or blink when trying to dim. Dimmable LED lamps allow you to adjust the brightness, which contain a special circuit that recognizes dimming and controls the lamp stabilizer circuit.
When dimming, LED bulbs behave differently from incandescent bulbs. When the incandescent lamp burns very weakly, the LED lamp still glows quite brightly. This is how the lamps look, connected via the same dimmer at minimum brightness.
All dimmers have a different minimum level. For example, in one of the Chinese dimmers, the waveform at the minimum level looked like this.
At the same time, LED dimmable lamps glowed quite brightly.
For dimming LED lamps, it is important that the minimum level of adjustment is as low as possible. If the filament of the incandescent lamp at the minimum level of adjustment glows a little dark red, such a dimmer is suitable for LED lamps, if the filament of the filament lamp is yellow, the LED lamps at the minimum dimming level will shine too brightly.
I connected the incandescent lamp to the three dimmers I have and measured the True RMS output voltage with a multimeter.
The black Chinese dimmer on the wire is 98 V. The
IKEA
dimmer is 66 V. The Chinese dimmer with a shiny handle is 46 V. The
maximum level for all dimmers is also different:
On the network is 228 V. The
black Chinese dimmer on the wire is 211 V. The
IKEA dimmer is 221 V.
Chinese dimmer with shiny handle - 220 V.
Dimmable LED lamps differ in the minimum level of dimming. Some allow you to reduce the brightness to 5%, and some only up to 20%. Here, for example, the Navigator NLL-C37-5-230-2.7K-E14-FR-DIMM and IKEA 102.667.54 lamps, included in the same dimmer at a minimum brightness level.
Another problem when dimming LED lamps is sound. Almost all dimmable lamps quietly itch when dimming, but some lamps with some dimmers begin to hum quite loudly. The dimmer itself can itch.
Another problem is the incompatibility of dimmers with LED lamps. Some dimmers "go crazy" when LED bulbs are turned on. I have a Univex switch in my room with dimming and remote control. When LED lamps are screwed into the chandelier, the light turns off immediately after being turned on. Replacing one of the six lamps with a conventional incandescent lamp helped. Now there are five LED lamps and one incandescent lamp in the chandelier and the switch works correctly.
The last problem is the incompatibility of the lamps and the dimmer. However, some LED lamps may not turn on or turn on once. For example, of the six lamps in the chandelier, when turned on, only five or four can be lit, and when turned on again, all six will be lit. The reason most likely is the interference introduced by the dimmer. For a Chinese black dimmer at half brightness, the output waveform looks like this:
It is possible that the interference pulse affects the operation of the lamp electronics.
Conclusions:
1. All dimmers have different minimum levels. LED lamps need to be as low as possible;
2. The maximum level is also different. If it is not high enough, the lamps will never burn at full brightness;
3. All dimmable LED lamps have a different level of minimum dimming;
4. Incompatibility of the lamp model with the dimmer model is possible;
5. When dimming, the lamps may hum, when changing the dimmer, the hum may decrease.
ps That's how I spend my day off. :)
pps Details have appeared on lamptest.ru for financial support of the project, in addition, now you can order testing of any lamp from any online store.
upd .: In addition to simple dimmers that cut off the leading edge of the sine wave (leading edge), there are dimmers that cut off the trailing edge and PWM dimmers. I have not seen such yet. Thanks to Ilya Savinkin for the tip.
© 2015, Alexey Nadezhin