There are many kinds of power adapter on the market, sometimes the same output power adapter, the price is a lot of difference, this is because the power adapter products due to circuit scheme and materials are different, and other electronic products are also divided into high and low, so where is the difference here?
First, let's look at the material of the shell. High-grade power even bite flower appearance, his texture and brightness is not the same, relatively bright, because it is a new fireproof plastic injection molding. And the low-grade appearance looks not shiny, gray. Because it is made of recycled plastic, the price of raw materials varies several times.
Secondly, you can look at the metal part of the material and plating. The exposed metal of many high-grade power supplies is copper nickel plating, or the thickness of electroplating will be relatively thick and the brightness is relatively high, because the high-grade power adapter should pass the salt spray test. Therefore, sometimes we will find that the phone charger bought outside for a few dollars will rust on the plug soon, while the charger of the original brand mobile phone will not rust after a long time. Of course, from the appearance can also see its label material, wire material and other places can see the difference between high-grade power adapter and low-grade power adapter. But there are also manufacturers may only spend the cost on the exterior, and do a particularly poor interior. That leaves the inside of the power adapter to be dissected.
If you know a little electronics, you can put the power adapter anatomy, low-grade power adapter, charger is generally used in the transistor scheme, this is the common name, in fact, is the professional name of the RCC circuit, it does not integrate IC to control, just the transformer and transistor self-excited oscillation. Some very low end chargers even have a single rectifier diode and may have no filtering capacitor behind it, or a small capacitor of 2.2UF. There's no photocoupling and no stabilized IC 431. There's no fuse on the front either. Such an ultra-low-grade power adapter composed of about ten components has no safety guarantee, high radiation and poses a threat to human health. Not to mention the use of electrical appliances, some protection of the power itself.
And high-grade power adapter input current fuse, bridge rectifier composed of four diodes or bridge stack, input filter capacitance is large. And EMI anti-electromagnetic interference components, so that the radiation to a minimum. The power supply is controlled by IC, and the feedback is controlled by primary PSRIC or secondary feedback mode photoelectric coupling and voltage regulator 431, so that the power adapter works stably. The power adapter complies with safety regulations. Each component has safety considerations. The whole power adapter has passed safety certifications, such as UL, CE, and CCC. Circuit built-in over voltage, over current, overload, short circuit and other protection functions, can better for the use of electrical appliances and power adapter itself very high protection function, so that electrical appliances and power supply are longer life.
So in the purchase of power adapters don't just see a lot of price difference, a penny of goods, high quality power adapter prices will naturally be more expensive.