An AC adapter is a type of external power supply which is enclosed in a case. It is used to draw current from the mains to powered appliances such as Laptops, TV sets, Decoders, powered music equipment and more. Other common names of the AC adapter include power adapter, power brick, wall wart, line power adapter, domestic mains adapter, adapter block, plug-in adapter, and plug pack.
The AC adapters are basically used for those electrical devices that require power but lack the necessary components to drive the power and voltage from the mains power.
How does the AC adapter work?
Before now, the AC/DC adapters were designed to consist of a linear power supply, with a transformer to convert the mains electricity voltage to a lower voltage, a rectifier which converts this voltage to a pulsating Direct current DC, and a filter which helps to smooth the pulsating waveform to DC, and variations from the residual ripple which is small enough to cause no effect on the powered device.
Basically, the AC adaptor works by converting the mains voltage into a direct voltage. This direct voltage drives a switching circuit containing a high frequency transformer. The whole process works to deliver DC current at a desired voltage.
In designing an AC adapter, the linear circuit needs to produce a specific narrow range of input voltages and must use a transformer that matches the frequency.
Let’s look at some of the advantages of the AC adapters
Safety. The power adapters transmit only low voltage that are good enough not to cause any hazard. Hence, manufacturers won’t have to worry over the safety of their products.
Electrical noise reduction: potentially noisy AC line power is converted to filtered DC current in the external adapter. This is a huge advantage to the AC adapter manufacturers.
Heat reduction: the adaptor helps to prevent any heat source from getting to the main device. This helps to increase the reliability and longevity of the electronic component.
Ease of replacement: due to internal generation of waste heat and the exposure to power spikes, the power supplies are more prone to failure than other forms of circuits. However, you can replace the external power supplies without having to repair the powered device.
Versatility of the configuration: with the help of the AC adapters, you can use an externally powered electronic product with a wide range of power sources, when traveling or when in your work place.
Simplified product certification, distribution, and inventory. An electronic device that is designed to be used in a broader range, across international borders needs to be powered from different power sources and should be able to meet up with the product safety regulations in the various jurisdictions. This requires more expensive certification processes from the agencies in those locations. However, an AC adapter for a certain powered device can be used in a wide range of countries with different power requirements. Hence, it can be manufactured, stocked and tested.