Power board packaging manufacturer: What is the overcurrent protection circuit?

Power board packaging manufacturer: What is the overcurrent protection circuit?

The power board is a safe place for the stable operation of electrical appliances in our life. There are many types and forms of circuits, and various protection elements are often used in the circuit to ensure the utilization of power. So what is the overcurrent protection circuit? Let's take a look with Xiaobian.

Power board packaging manufacturer: overcurrent protection circuit Circuit introduction

Overcurrent protection is realized by connecting quick fuse in series in the circuit. It is applicable to thyristor and GTO because they have higher surge current tolerance. For MOSFET, GTR and IGBT, due to the low over-current capacity, special over-current protection circuit is required. It is required to complete over-current detection, signal transmission and protection actions in an instant and microsecond. The internal current is limited by the overload capacity. At present, the commonly used methods are: monitoring method and current sensor protection method

Definition of overcurrent protection: Many electronic devices have rated current, and it is not allowed to exceed the rated current, otherwise the device will burn out. Therefore, some devices have made current protection modules. When the current exceeds the set current, the equipment will automatically cut off the power supply to protect the equipment. For example, the main board usb generally has usb overcurrent protection to protect the main board from burning

Power board packaging manufacturer: principle of overcurrent protection circuit

When the inter-phase short circuit fault occurs, the grid current will suddenly increase and the voltage will suddenly drop. Overcurrent protection is to set the working current of current relay according to the requirements of line selectivity. When the fault current in the line reaches the action value of the current relay, the current relay acts according to the selection requirements of the protection device and selectively cuts off the fault line

Effect: It is said that a material has PTC effect, that is, positive temperature coefficient effect, which only means that the resistance of the material will increase with the increase of temperature. For example, most metal materials have PTC effect. In these materials, PTC effect shows that the resistance increases linearly with the increase of temperature, which is usually called linear PTC effect

Overcurrent protection circuit is the main method of circuit protection. Overcurrent protection also provides protection for circuit insurance to ensure less loss of circuit equipment and protect equipment and personnel

Power board packaging manufacturer: Can the varistor really prevent lightning stroke

In fact, first of all, we need to understand the invasion modes of lightning stroke: direct lightning, inductive lightning and lightning wave invasion. The specific meaning has been explained in the previous article. I won't repeat it here. Here we only talk about the lightning protection of varistor. If you thunder directly, even a tough iron wall may break you, let alone this small chip? This is a mess for you. For direct lightning, our old lightning rod will naturally take care of them. Our varistor officially protects against induced lightning waves rather than direct lightning strikes. Then netizens will do it again. How did he prevent it

Power board packaging manufacturer: pressure sensitive resistance movement

The pressure sensitive resistor is a voltage limiting protection device. Using the nonlinear characteristics of the varistor, when overvoltage occurs between the two poles of the varistor, the varistor can clamp the voltage to a relatively fixed voltage value, thus realizing the protection of the subsequent circuit. The response time of the varistor is ns. What is the concept of NS? The air switch you usually know can only reach microsecond level. The response speed of the air switch, as you should know, is basically available in every home, but there is a problem with the circuit. When brushing teeth, the air switch is closed, so this is its speed. Then, compared with the speed of this varistor, it is insignificant, nanosecond. The multiple is the third power of 10, which is thousands of times. This is unimaginable, so don't look at such a small thing, but it has such a big impact