Jul 162013

Adapters are power supply devices that change the electric-network voltage (in most cases) to values ​​and type, suitable for the operation of various electronic appliances. Practically all the electronics that surrounds us works with much lower than the mains voltage and as there are no low-voltage electrical systems in our houses, we need to use devices that reduce the voltage from 220VAC to the suitable voltage planned for the operation of consumer electronics. Whether it’s a TV, a mobile phone, a PC, a laptop or a tablet, we need a mediation device to achieve low and often constant voltage. Sometimes the adapter is located in the electronic device such as a TV or a computer, and sometimes it is separated from it, such as a laptop, a phone, etc. and can be easily changed, if burned.

adapter reguliruem

Adapters are divided into transformer and switching, stabilized and non-stabilized, adjustable and non-adjustable, adapters converting the mains voltage and adapters which are plugged in the cigarette lighter of the car and work with 12VDC constant input voltage. There are AC / AC adapters, DC / DC adapters and AC / DC adapters. AC / DC adapters are rectifiers which, according to the principle of operation, are divided into two main groups: linear and switching. AC / AC adapters are usually transformer and they don’t change the format and frequency of the input voltage. They change only the value of the output voltage. DC / DC adapters are used when we want to plug in a device designed to operate at 12VDC, which is the voltage supplied from the battery of the car, lorry, bus or ship, where the voltage is 24VDC. Adapters can be wired or wireless.

adapter no cable

Adapters that provide the plugged-in devices with the necessary voltage but they cannot charge them are also called power supply devices, or just power supplies. There is another type of adapters that can charge the battery of a laptop, the battery of a wireless phone or wireless headphones. They are called chargers. Chargers are adapters which are non-stabilized. This means that at idle running the output signal will be about 20-30% higher than the signal for which they are designed. In other words, if we have a stabilized adapter which provides 9VDC at its output, at idle running we can measure 12 or even 14-15VDC at its output. Only when we connect load (consumer), its voltage will become close to the nominal one.

adapter vratka

This type of adapter, as already mentioned, is called charger adapter. Chargers of this type have the function to switch-off after charging the battery, to which they are connected. This prevents the battery from overcharging which is harmful for it and shortens its life considerably. There are also stabilized power supplies, which are not equipped with the function to switch-off after charging the battery. They can be used as chargers, but must be monitored and disconnected in time, before the battery is overcharged.

adapter 1
The main parameters of adapters include their maximum power, which is usually indicated in amperes on their housing, the largest operating current, at which they can operate for long periods without overheating and damage, and their polarity. Adapters are interchangeable, but you must keep the following principle: an adapter with maximum current 1A can be replaced by an adapter with the same or larger maximum current, but not smaller. Adapters are also divided into ones with „+“ in the center of the connector and „–“ at the periphery and vice versa.

adapter orange

There are also multi-purpose adapters, whose connectors are detachable, and can change their polarity. You must be careful when using a multi-purpose adapter in the place of another one, which isn’t multi-purpose. You need to keep the polarity of the consumer, because if the polarity is wrong, this can damage the device, which will be powered by the adapter. You can measure the polarity of the consumer with a multi-meter to verify that the connector of the multi-purpose adapter is positioned so as to supply electricity with the same polarity. Adapters whose secondary voltage can be selected by turning a miniature switch through a screwdriver or a slider are very suitable for daily use.

car adapter

So an adapter can supply power to a lot of devices. In order to become multi-purpose, an adapter is equipped with a series of terminals that can be replaced. Another trick used by manufacturers of electronics to make their power supplies multi-purpose, regardless in which country they will be used, is to expand enormously the allowed primary voltage to which the power supply of a laptop can be connected, for example. We know that in the US, England, Japan, Canada and other countries, the electric-network voltage isn’t 220VAC, but around 110VAC, depending on the country, as discussed in detail in the article „Convectors“.

110-240 12VDC stabilized 6A

In order to avoid the use of convectors, the voltage of the power supply of laptops is made so that they can be plugged in the entire range from 110 to 240VAC. Many of these adapters have different plug caps. This avoids the use of transitional adapters for switching from one standard to another (from European to American or English or vice versa).

Feb 282013

led lights

Switched-mode power supply units are power supply devices of a modern type, they are highly efficient, small sized and have low weight.

switching_power_supply_psin10012Switched-mode power supplies rectify and stabilize the voltage needed to supply power to an appliance operated by DC, a LED lamp, LED rope light, CCTV cameras, promotional items or other devices. They rectify and correct the current pulse, clearing the interference in it. In technics they are also called key stabilizers whose main operating principle is to maintain the value of the output voltage constant.

Switched-mode units serve to convert the current with mains frequency (50/60Hz) into current with high frequency (50 kHz), which provides much greater power and efficiency. This feature is combined with small and compact size, and with far less weight than standard transformer solutions, which makes switched-mode power supplies very popular in everyday life.


 Waterproof LED Driver

The size of a switched-mode power supply is determined by its power, and the higher the power is, the more massive the power supply is. These power supplies are produced with different primary and secondary voltages designed for powers from a few watts up to 1,000 W. It is sometimes more practical if a switched-mode power supply has more than one secondary voltage (usually 12 VDC and 24 VDC)

The efficiency of switched-mode power supplies in contemporary models can reach 93%. This in turn leads to reduction of losses in the form of heat dissipation in the environment. The more powerful and less precise switched-mode power supplies still produce heat, so they need a fan that provides them with the necessary cooling. Most modern switched-mode power supplies have overvoltage, overload and short circuit protection, which makes them a reliable and durable energy source.

original_31928 Waterproof LED power supply

One of the drawbacks of switched-mode power supply devices is that they emit a high-frequency signal, which may lead to electromagnetic interference in computer systems and precise devices (such as a pacemaker). Therefore, switched-mode power supply units have a metal casing, which absorbs the majority of these emissions, and the larger and more powerful ones also have an EMI filter.
According to the environment in which they operate, there are waterproof and non-waterproof switched-mode power supplies. Waterproof power supply units can be used to supply high power LEDs, LED rope lights and LED tapes, they have a waterproof casing and IP65degree of protection, which makes them suitable for outdoor installation. Non-waterproof power supply units are designed for indoor use and have perforated casing for better cooling. According to their implementation they can be mounted on a DIN rail or in a standard way.


DIN rail switched-mode power supply

The massive influx of switched-mode power supplies in our everyday lives enhances the requirements towards their designers to reduce the size, weight and interference of these devices. Nowadays switched-mode power supplies are becoming more and more functional and ergonomic.