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Guideline: Find the right 12 Volt power supply for your application

General information about dimmable LED transformers for the operation of LED retrofit lamps (low voltage, GU5.3, GU4, ..)

If dimmability is to be maintained, all three components must fit together. The LED spotlight must be dimmable, the LED power supply should also be suitable for dimming, and also be compatible with the phase or section dimmer. Since there is no standardized interface here, a look at the compatibility lists is worthwhile, for example, to avoid flickering. Basically, however, a compromise must be made with this solution in terms of dimming comfort. The usual dimming behavior of being able to dim down to a few percent (100% - 1%) is no longer possible with this technology.

For dimming via phase control, 12V LED transformers and lamps for AC (alternating current) should be used.
The reason is that the operating electronics of the dimmable LED power supply also require energy for the generation of stable LED current. Flickering or undefined switch-off is the result.

Accordingly, pure LED solutions with constant current sources are increasingly used for the operation of LEDs. This is done in conjunction with controls via 1-10V, DALI, touch dimming or even via radio. Here we present the operation of constant voltage sources.

The right dimmable LED ballast for LED strips

When operating LED strips, on the other hand, you will now find many options using a 12V power supply. On our lighting control pages you will find a variety of suitable LED ballasts with different power ratings and control inputs, as well as dimming concepts. These are explained in short form below.

Dimmable LED power supply and its variants explained in detail

While incandescent lamps can be dimmed relatively easily by reducing the voltage, this is no longer quite so simple with LED strip dimming, LEDs are electronic components, so-called semiconductors and require a certain remaining voltage to light up.  Under the threshold value nothing happens and only from a certain voltage value, the brightness increases sharply. For this reason, a detour is taken via a current control, implemented via additional electronic components. These convert the input voltage into an analog current for the LEDs, so that the following dimming variants are possible.

Variant 1 - Voltage variation

The LED control gear for e.g. 12V is reduced in output voltage, which rarely leads to uniform brightness

Variant 2 - PWM dimming

The operating voltage is switched on and off for different lengths of time (pulse width modulation).
The operating devices must be aligned accordingly and this in dependence of different control possibilities on the user side. These PWM dimmers

Option 1 - The transformer itself is conventionally dimmable.

Special dimmable LED transformers can be used via standard phase or section dimmers, which are often already available in existing buildings. In this case, the LED transformer is switched directly after the phase dimmer. The LED strips are connected to the LED transformer without any further electronics. This solution is often used when only the existing three lines (L,N,PE) are available in the house installation. Disadvantage: Limited dimming range, as already known from retrofit Solutions.

Option 2 - LED power supply is dimmable via external control line

Many manufacturers offer LED transformers with an additional control input. There, for example, the output voltage can be changed or switched via a control voltage such as 1-10V, a potentiometer, a DALI signal, or a PWM signal.
The principles are different and depend on the type. This solution is also often combined with wireless modules (e.g. Casambi).
Dimmable LED transformers are particularly suitable if the LED strips have only one light Color.

Option 3 - Fixed voltage transformer with additional PWM dimmer

The operating voltage is switched on and off for different lengths of time (pulse width modulation).
The operating devices must be aligned accordingly and this in dependence of different control possibilities on the user side. LED power supplies with 12V fixed voltage are used in combination with a dimmer.

This variant offers maximum flexibility and is also suitable for retrofitting in existing installations. The additional PWM dimmer is installed between the power supply and the LED strips. The setting of the desired dimming level is possible in many different ways (DALI, push button, 1-10V, radio, Bluetooth, Wlan with additional module). This solution allows to control not only single color, but also multicolor (DUAL-White, RGB, RGBW) LED strips.

Option 4 - LED power supply 12V with integrated PWM dimmer

his is a LED power supply where the dimming level can be adjusted directly via DALI or DMX interface. The 12V power supply is directly supplied with the power supply (230V). The LED strips are also connected to the power supply unit. The advantage here is that only one component is needed for dimming. The control is done via the integrated DALI or DMX interface.
We increasingly recommend the Meanwell PWM series.

Do not hesitate to send an inquiry to our experts for LED strips. We will be happy to advise you. Or scroll down for more details on this page. Dim LED strips - detailed description or use our selection guide for LED transformers.

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