Main power source
Standard power supply provided in the lamp design.
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Net. Powered by a regular household 230V socket. This is the option provided by most table lamps: sockets provide unlimited runtime and are ubiquitous (and where they are not available, you will need a portable flashlight rather than a table lamp). The only significant drawback of this type of power supply is the presence of a wire; however, it usually does not create any noticeable inconvenience, and problems with reaching the outlet are rare and easily resolved.
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Batteries. Powered by replaceable batteries (AA batteries, AAA batteries, etc.). Such batteries can be either disposable or rechargeable. Such power allows you to use the lamp without connecting to an outlet, and the batteries themselves can be quickly replaced when their charge is depleted (unlike built-in
batteries, see below). At the same time, table lamps are intended mainly for residential and work spaces, where there are no problems with sockets. At the same time, autonomous power supply inevitably limits the operating time of the lamp, and batteries in particular are suitable only for relatively low-power lighting sources. Therefore, this option is used only in cases where the wire is undesirable or inappropriate. For example, some children's's lamps with a night light function are powered by batteries (so that there are no unneces
...sary wires in the children's's room), as well as decorative models in an unusual design (so that the power cord does not spoil the appearance).
- Battery. In this case, we mean an original battery that does not belong to standard “battery” sizes and does not allow for quick replacement (sometimes it is not removable at all). Actually, the inability to quickly replace is precisely the main disadvantage of such power sources compared to the batteries described above. On the other hand, batteries can be made more capacious and at the same time more compact; they are easier to fit into the design of a lamp (even a very small one); and the fact that such food does not need to be purchased separately can also be considered an advantage. Thanks to this, batteries are found more often - both in original lamps, where wire is in principle undesirable, and in lamps for work purposes (mainly LED).
— USB port. Powered by standard USB port. This category of lamps will be appreciated mainly by laptop owners: when working with a laptop, the USB ports are in close proximity, and connecting lamps to such a connector is easier than looking for a socket and pulling a wire to it. However, such a device can also be connected to an outlet - just find a 230-to-USB adapter. USB adapters also exist for car cigarette lighters, so such a lamp can also be useful for mobile use - for example, when traveling outdoors or in the van of a mobile group (scientific, operational, etc.). And if necessary, you can power the lamp from a battery - a separate power bank or the same laptop. At the same time, in general, the scope of application of USB lamps is quite specific, and there are only a few of them produced.Luminous flux
Luminous flux provided by a lamp. This parameter is indicated only for models using built-in LED modules (see “Light source”) - in lamps with a socket, it will depend on the light bulbs used.
Luminous flux is essentially the brightness of the lamp. The brightness itself in lumens tells little to the average user, a non-specialist; however, there are tables that allow you to compare the luminous flux of a lamp with a particular light source of standard brightness. For example, a 40 W incandescent lamp produces about 415 lm, a 60 W lamp produces 710 lm, and a 100 W lamp produces 1340 lm. More detailed tables for comparison can be found in special sources.
Speaking of brightness, it is also worth noting that it should not be too low or too high: both create discomfort, increase fatigue and can lead to eye problems. Reference sources provide recommendations on optimal brightness for different tasks. However, this point can be determined for yourself experimentally. And if in doubt, you can purchase a lamp with adjustable brightness (see “Functions and capabilities”).
Colour temperature
The colour temperature of the light emitted by the lamp. It is indicated only for models with built-in LED (see "Light source"), since bulbs with different characteristics can be installed in the socket. In luminaires with
colour temperature control(see "Features"), the minimum value is usually taken into account.
This parameter directly determines the hue of the visible colour. At the same time, its physical meaning is such that as the colour temperature rises, this shade becomes more
“cold”, shifts from yellow to blue. Here are some examples of colour temperature, for clarity:
— 1500 – 2000 K — candle flame;
— 2800 K — 100 W incandescent lamp (
warm light);
— 4000 K — a fluorescent
lamp of daylight white light(such light can already be perceived as cold);
— 5000 K — the light of the midday sun;
— 5500 K — a shade from white clouds at noon;
And so on, thickening to blue cold shades.
Note that the choice for this parameter depends not only on personal preferences and design considerations, but also on the general purpose of the lamp. So, a high colour temperature (from 5000 K) is considered optimal for reading, an average colour temperature (about 4000 – 5000 K) is comfortable for mathematical calculations, working with documents and other tasks that require concentration, and
...soft warm light up to 4000 K is good for relaxing and creating atmosphere of comfort.USB charging
Possibility
of charging the battery from a USB port. This function allows you to replace the power cord if necessary if it becomes frayed or lost. And there are advantages to ease of use: the battery can be recharged from the USB port of a power bank or laptop. In this case, the connector in the device itself can be microUSB, USB C, or a proprietary one, which will require an appropriate cable (included in the kit, but replacement will be more difficult).
