Difference between power adapter and charger and the danger of non-safe power supply
May 15, 2018
What is a power adapter, what is a charger, and what is the difference between the two, why not universal?
First of all: power adapter It belongs to an external power supply, simply to provide power conversion equipment for large and medium-sized electronic equipment and electronic appliances, its role is to convert 220 volts AC high voltage to the normal operation of the electronic equipment 3.3V to 73V or so low voltage DC, so that electronic equipment can work properly, and is widely used in mobile phones, notebook computers, security equipment, various types of instrumentation equipment, advertising machines, light boxes and other products.
Second: The traditional linear power adapter consists of a transformer and a rectifying filter circuit. This is not only bulky, but the voltage regulation effect is also not optimistic, and the power conversion rate is low. The switching power adapter adopts a miniaturized fully-sealed switching power supply module without a power frequency transformer, and has a good voltage stabilizing effect and a small power conversion rate, and can completely replace the linear power adapter. For example, the adapter of a notebook computer is wide voltage and can automatically detect 100 to 240 V AC. Basically all notebook computers will put the power supply externally, and then use the line and host to connect, so as to achieve the purpose of reducing the size and weight of the computer. Note that a friend who reads knows that there will be a nameplate on the adapter indicating the power, input and output voltage and current, etc. Since each standard voltage used in different countries and regions is different, it is assumed that the input of a foreign adapter is 100V. The input voltage, if used in the country will be burned by the 220V voltage in China!
What is the significance of the voltage and current marked on the nameplate of the power adapter? The voltage indicated by the general power adapter means that the output of the power adapter is not connected to any electronic equipment and there is no voltage when the load is applied. The power adapter internally uses an active-stabilized sampling feedback loop. Even if the input AC voltage changes, the output is a constant value.
Under normal circumstances, the no-load voltage and the nominal voltage of the power adapter are not exactly the same, because the current will have a small loss when passing through the DC wire, so the no-load voltage of the power adapter is usually set higher than the standard voltage. . The current value, it represents the power adapter's carrying capacity. Any power adapter rectifier diode and output DC wire will have a certain internal resistance, so when the power adapter is in the output, it will cause losses in the rectifier diode and DC line, which will lead to power adapter heating and voltage reduction.
There is a difference between the no-load voltage of the power adapter and the voltage after being loaded. In general, the deviation is within ±5%.
The above summarizes the difference between the power adapter and the charger: The charger can convert AC power to low voltage DC power; it can directly charge the battery. The power adapter is a power converter that has been transformed, rectified, and regulated. The output is DC, and the battery cannot be directly charged.
The safety of non-safe power supplies
Non-safety products have potential safety hazards and threaten the safety of life and property of users. Non-safety switching power supplies are prone to short-circuits under dust, moisture, high temperature, lightning, vibration, etc. Once a short circuit occurs, non-safety power supplies It is highly prone to cause electric shock and fire. It is strongly recommended that customers carefully choose non-safety power supplies for their own brand reputation and safety of end customers' personal and property, so as to avoid irreversible losses.