Overview and selection of dimmers for different light sources

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• What you need to know about the dimmer device
• Dimmer selection by lamp type
• Mechanical resistive dimmers
• Electronic multifunctional dimmers
• Modular dimmers – why you need it

Dimmers have become quite familiar to the layman, but their use still hides quite a lot of pitfalls. In the article, we will reveal the essence and principle of operation of these devices, which will help you decide on the type of dimmer to be purchased and how to install it..

Over the past few years, many dimmer modifications have been made and their functions are no longer limited to simple dimming. A modern dimmer is an excellent means of automating the lighting network, with the development of electronics, their work has become almost flawless, and the disadvantages have been minimized. To better understand the scope and operation of these devices, you should first familiarize yourself with their evolution.

What you need to know about the dimmer device

The first attempts to vary the brightness of the glow of the lamps assumed the use of conventional variable resistors for this. By increasing its resistance, it was possible to limit the current and reduce the heating of the spiral. The problem is that such a dimmer itself acts as a consumer and the heat power dissipated by it must be high enough (40-60 W).

To eliminate the drawback, it was decided to control the voltage in the circuit, which requires a semiconductor switch. Instead of a rheostat, they began to use less powerful, but more accurate potentiometers that regulate the control current of the thyristor. This allows you to “cut” the sine wave at voltage peaks, and in order to compensate for the lamp damping during the absence of current in the circuit, the dimmer was equipped with a capacitor.

The power of the semiconductor elements remained quite high, which is why the dimmer created interference, the effect of which on the transmission of a radio signal (FM receivers, wireless Internet) was negative and quite tangible. To reduce interference, chokes on ferrite rings (filters) were used, so modern dimmers practically do not affect the operation of radio equipment..

Dimmer selection by lamp type

This approach is very good for driving the resistor resistor, which is essentially a lamp spiral. But for switching power supplies, such as electronic ballasts of fluorescent lamps, including “housekeepers”, this system is not suitable.

Trying to control the voltage at the base of an energy saving lamp will either not work at all or will reduce the lamp and dimmer life to about 200 hours. To be able to harmlessly control the brightness of the filament, the dimmer must be included in the electronic ballast circuit, therefore, either special lamps with control contacts or ballasts are always supplied with the regulators.

To control the brightness of energy-saving lamps, rather complex microcircuits are used – half-bridge drivers that have the functions of lighting the lamp and maintaining its brightness in a certain range. But standard microcircuits support only step regulation: for example, using the simplest driver, you can set two levels of brightness for the lamp. To increase accuracy, the microcircuits are installed in a cascade – two for 4 switching positions, three for 8 levels, four for 16 levels, etc. Accordingly, the more smoothly such a dimmer adjusts the brightness, the more expensive it is..

In the case of LED lamps, everything is somewhat simpler – special types of dimmers can change the supply current, respectively, the transformation current will also change. But to control RGB light you need 4 control wires and three different dimmers. Therefore, the regulator is often installed either after power transformers, or combined with them in a so-called driver. The main disadvantage of such devices is the low voltage of the control circuit, so the distance from the driver to the regulator should be minimal. The dimmers used for this are marked R – resistive, L – inductive and C – capacitive for use with the corresponding types of loads and transformers.

Mechanical resistive dimmers

Despite the active introduction of energy-saving lamps, conventional filaments are still popular due to the more natural temperature of the light emitted. So it’s too early to write off mechanical dimmers. They are optimal for working with incandescent lamps due to their low cost and prevalence..

According to the control method, dimmers are divided into push-button, rotary and rotary-push. The advantage of the latter is that they have a memory: turning on the dimmer is possible in any position of the handle, while rotary ones start only with a minimum brightness.

Pushbutton dimmers are less convenient, but using pushbuttons instead of a potentiometer makes the knob more durable and less expensive. You should be aware that mechanical dimmers have a high threshold (20–40 W) of the minimum switching power and this must be taken into account if there are parallel-connected lamps in the network: if one of them burns out, the whole chain will stop working. Also, dimmers somewhat extend the service life of incandescent lamps: they eliminate the inrush of current through the lamp in that short period when the coil is not heated and its resistance is very low.

Electronic multifunctional dimmers

The convenience of using equipment is very important for a modern person. Advanced electronic dimmers have a number of great features:

1. Dimmers have convenient control with buttons or mnemonic sensor.
2. The soft start function is to automatically dim the light when turned on and off. Looks very attractive and comfortable in household use.
3. Scene presets allow you to set multiple brightness levels and switch between them at the touch of a button.
4. It is also possible to automatically turn on and off according to a daily schedule, the so-called imitation of presence. Talking about the benefits of the automatic shutdown timer will be superfluous..
5. The digital transfer of data between the system components reduces the cost of organizing multiple lighting control points, which is useful in large and walk-through rooms. Several lines can be controlled from one single panel, all network elements work independently of each other.
6. Advanced electronic circuitry means high efficiency (over 90%) and low power consumption. Due to this, it became rational to use dimmers for auto-conversion of lighting to night light mode.

Modular dimmers – why you need it

There is a separate class of devices that are used in the construction of centrally controlled lighting networks. It is much cheaper to install one multichannel driver than buying multiple dimmers per line. But at a load over 200-300 W, the dimensions of the device and the heat release do not allow installation in the switch box, moreover, it is obvious that the switching device should be installed as close to the consumer as possible, saving the cable.

If there is a sufficiently capacious ASU shield, the dimmer can be placed in it and the connection with the control panels with a thinner wire, for example, a twisted pair, can be organized. If the power supply project provides for room group shields, dimmers are installed in them to control only 1-3 lighting lines.