In a series regulated power adapter, all load current flows through the regulator. When an overload occurs, the large-capacity capacitor is instantaneously charged, or the output is short-circuited, a large current flows in the regulating tube. In particular, when the output voltage is short-circuited by accident, all the input voltage is applied between the collector and the emitter of the series adjustment tube, so that the heat generation in the tube is drastically increased. At this time, if there is no proper protection, the pipe will burn out in an instant. The thermal inertia of a transistor is smaller than that of a blown fuse, so the latter cannot be used to protect the former. The series regulator tube must be protected with a fast reactive electronic protection circuit. The electronic protection circuit can be divided into two types: current limiting type and current blocking type. The former limits the regulating tube current to a certain safe value, while the latter immediately cuts off the regulating tube current when an overload or short circuit accident occurs at the output end.

The regulated DC power adapter generates a strong negative voltage, then connects one of its sections to the cathode, one section to the anode, and then creates a strong electric field between the cathode and the anode, which is discharged after the two-pole electric field exceeds the specified intensity. At this time, ionization occurs around the electric field, and then a large amount of electrons and ions are generated. After a while, you can hear a strong electromagnetic sound around the electric field. Moreover, a lot of tar, dust and other particles and ions or electrons are combined around the electric field. This charge will move toward the poles under the action of the electric field force. The quality of electrons is extremely small, but its speed of movement is particularly fast, so it is mainly driven by negatively charged particles.