What Makes a Good AC Adapter?

An AC Adapter is essentially an external power supply unit that derives its power from a mains power supply and converts that current and voltage to that required by the portable device. Having an external AC Adapter means that the device it is designed to provide power to, does not have to have an onboard power supply, but merely the capability to receive the power.

The early AC Adapters were referred to as linear power supplies that used a transformer to reduce the mains voltage of between 110-240 Volts to that required by the portable device. A lot of the earlier AC Adapters were fairly large and heavy for their size due to the fact that they contained all the circuitry for a transformer. In fact their weight was such that their weight was difficult to support directly from a wall outlet. They generated a lot of heat and their output voltage could vary without the addition of a linear voltage regulator.

Switched Mode Power Supplies (SMPS) became the next evolutionary step, because they rectify the voltage to a much higher voltage, and through a switching circuit, they produce an output current at the required level. Because of the higher frequencies involved, the transformers used with SMPS were much more compact and lighter than their counterparts. Another advantage of the SMPS is the fact that it can operate over a much wider range of voltages. I remember an early Sony VAIO that had a huge heavy ac adapter, it would hardly fit in my laptop bag!

Whenever a laptop is to be packed away for transportation, the ac adapter is removed and can, in some instances be lost or mislaid. I shudder to think of how many mobile phone adapters I have left in hotel rooms over the years, after having charged my phone. This has conspired to create a very large market for replacement ac adapters. Manufacturers use different connectors, so an AC adapter, for example designed for a Dell laptop might well not fit a Toshiba laptop. Also, the voltage requirements for one manufacturer’s laptop might be different to that of a competitor. This has resulted in a number of AC adapter manufacturers designing universal ac adapters to fit a wide range of laptops that require a different connector. Some even have a range of output voltage settings to suit whichever brand of laptop it is required to power. Some of these designs incorporate four-way or 6-way connectors , while others come with a number of interchangeable tips.

So, it is important when choosing a replacement ac adapter, and in particular a universal ac adapter that you check to ensure that:

1.  It has the correct sized plug or plugs to match your laptop or laptops.

2.  The input and output AC and DC voltages match those where you are intending to use the device.

3.  The current supplied by this ac adapter meets the requirements of your laptop.

Most of the recent universal  AC adapters are of the switched-mode power supply type and will ensure you have a more reliable output voltage, even under variable load conditions. The other important point to note is that they will generally be small and light, although if you choose an AC adapter model with interchangeable tips, they you will have additional items to carry in your laptop bag.

In the UK, Origin Storage manufacture a range of Universal Power Adapters designed for use with a number of different manufacturers range of Laptops such as Dell, Acer, Sony and Toshiba. In my opinion they are well made and offer good value for money.

This article on Universal AC Adapters was written by David Christie, MD at NSTUK Ltd,  Website: http://www.ipexpress.co.uk .

What is a Portable Battery Charger?

The term battery charger relates to a number of devices used to induce energy into a rechargeable battery to replenish its power supply capabilities. These days we use battery chargers for many applications, and a lot of our mobile devices and digital appliances such as cameras have rechargeable batteries that need regular topping up to ensure the device remains functional.

The amount of charging that a device requires depends on the type and rating of batteries in use with the device. Some devices can withstand a constant sustained charging source and are not damaged or impaired should that charging source remain in place even after the batteries have been fully charged. Other devices will cut off the current to the batteries once they reach full charge. Some chargers employ a trickle charge, supplying only a small amount of current that can take several hours to charge a battery, whilst others can charge batteries in under an hour.

There are many different types of battery chargers available which employ many different methods, and we will only mention one or two as we concentrate on chargers employed for mobile phones, Smartphones, iPhones, iPods and iPads, which we often refer to as a portable battery charger.

One type of charger of note is the induction charger which uses a form of electromagnetic induction by transmitting electrical energy by means of some form of inductive coupling. For quite a number of years now they have been designed for use in environments where normal chargers may represent a risk of electrocution, such as bathrooms and other areas where the user may come into contact with water. Electric toothbrushes are a good example of objects that may use an induction charger. Powermat provide a range of induction mats designed to wirelessly charge a selection of smartphones, including the iPhone range.

Probably the biggest use for battery chargers is in the mobile phone market, and in recent years standards were developed for charging mobile devices using USB connections. The microUSB connector was developed specifically to connect a USB cable to a mobile device such as a phone or a digital camera. Voltages on USB connections are designed at or around 5 Volts with a maximum of 5.25 Volts, so they are ideal in most situations due to the low voltages involved. Since 2009 most of the major mobile phone vendors agreed to standardize the use of Micro-USB as the interface on mobile phones for the purpose of charging the batteries.

A popular type of charger is the in car battery charger for use with devices such as mobile phones, MP3 players and SatNav models. They receive their power via a connection with a car cigarette lighter and have an input range of somewhere between 12 and 24 Volts and output 5 Volts at 1 Amp current. Some of these chargers even come with a selection of connector tips to make them compatible with a range of popular mobile devices. A good example of a universal car charger is the Belkin F8Z689CW which is designed to charge your Apple device such as iPad, iPhone or iPod whilst on the move. This compact device sits neatly in your dashboard and connects to your cigarette lighter, providing a 3 foot cable for connection to your mobile device.

There are a wide variety of mobile battery chargers and adapters currently on the market specifically designed for use with mobile devices, and it really just depends on the model that suits your needs. I would certainly recommend buying a model from a well known manufacturer, particularly as a lot of cheaper copies have flooded the market in recent months, some of which have been found to be faulty, and in some cases dangerous.

This article on mobile battery chargers was written by David Christie, MD at NSTUK Ltd, Website http://www.ipexpress.co.uk/Chargers-Power/b/1569153031