Tuesday, November 29, 2022
Tips and Tricks

# What happens if the wrong power adapter is used?

Can 12V be used for 9V power supply

1. It is not allowed under normal circumstances. The short-term use may not cause problems, but the long-term use may lead to the danger of directly burning the equipment;

2. Although the circuit generally has overload design, too large input voltage will exceed the setting of the internal circuit and parts, which is likely to cause damage and even explosion;

3. Unless the appliance you need to use supports wide voltage input and 9-12v input voltage, 9V power supply cannot be replaced by 12V;

## Precautions for using the wrong power adapter

If the appliance supports wide voltage input of 9v-12v, it can use 12V power supply, otherwise it cannot be used, and the replacement power supply voltage should be the same. If the allowable error of different replacement power supply voltage is generally ± 5%, more than 10% will burn the appliance, less than 10% of the appliance can not operate normally, and 12V exceeds 9V 33%, the appliance cannot use 12V power supply.

As the power input of the electronic equipment has a certain range, there is also a voltage stabilizing circuit inside the machine to supply power to the whole machine. For example, the rated voltage of some electrical appliances is 220V, and the input range can reach 180v~240v.rogers pcb

The power output of the wireless router adapter is 9V, 0.6A. Although the 12V, 1A adapter is slightly larger than the original adapter, it is not much higher, and there is a small transformer inside the power supply to stabilize the voltage, which is within the allowable range of the router. Therefore, this adapter can be used instead.

#### What does the nominal voltage and current of the power adapter (hereinafter referred to as the power supply) mean?

First of all, the nominal voltage of the general power supply refers to the open circuit output voltage, that is, the voltage when there is no external load and no current output, so it can also be understood that this voltage is the upper limit of the power supply output voltage.

When active voltage stabilizing elements are used in the power supply, even if the mains voltage fluctuates, the output is constant. For the power supply equipped with small transformers in the market, such as Walkman, if the mains voltage fluctuates, the output of the power supply will not fluctuate.

Generally speaking, the true no-load voltage of an ordinary  may not be completely consistent with the nominal voltage, because the characteristics of electronic components may not be completely consistent, so there is a certain error. The smaller the error, the higher the consistency requirements of electronic components, the higher the production cost, so the price is more expensive.

In addition, with regard to the nominal current value, no matter what power supply has a certain internal resistance, when the power supply outputs current, there will be internal voltage drop, resulting in two things: one is to generate heat, so the power supply will be hot, and the other is to reduce the output voltage, which is equivalent to internal consumption.

the authorAmy Rey
Lifelovesu2@gmail.com