What is an ac power adapter?

The AC adapter is an external power supply component that converts alternating current to direct current, usually encapsulated in a plastic case.

The input voltage ranges from AC 100V to 240V, and the output DC power is suitable for electrical appliances. The AC adapter can be used with some electrical appliances that the power be required, but there is not internal circuit to convert the AC power from the mains to the internal power supply. Sometimes, the electrical appliance used with the AC adapter also has a rechargeable battery inside. The transformer not only provides the electrical power supply, but also provides the power supply for battery charging.

There are both advantages and disadvantages here for the AC power adapter as following:

Advantages:

1. Safety: there will be no dangerous voltages within the device's enclosure, and similar hazards need not be considered in the electrical design.

2. Lower the tempeture: the main heat will be in the AC adapter, and the device can be protected because itself will have less heat source and lower temperature.

3. Reduced electronic noise: if the AC power line or car power supply with a lot of noise is changed to a DC power supply with less noise and filtering provided by the AC adapter, the radiated noise will only be generated on the AC adapter, leaving the circuit that is easily disturbed by noise.

4. Easy to be replaced: If the external AC adapter is damaged, as long as the specification information is known, it can be replaced directly without repairing the damaged power supply circuit.

Advantages of AC adapter with 4 different types AC plugs

1). Strong configuration versatility: 

2). Simplified product inventory, sale and certification: The product only needs one type in manufacturing, inventory and testing, as long as the AC adapter meets the safety requirements of the countries Specifications can be. The AC adapter itself does not need to be retested if the design of the product has changed (as is often the case in consumer products).

Disadvantages:

1. Size, weight and Inefficiency.

2. Confusion: External AC adapters don't look very different and don't clearly identify which device it's designed to power.

3. Compatibility: There is currently no consistent standard for the connector of the adapter to connect the device. It may be that the two AC adapters are the same connector, but their voltages are different or the polarities are opposite. So an AC adapter may be structurally connectable to another appliance, but its voltage or polarity definition is reversed, which could result in damage to the appliance.