Connection mode of switching switch in circuit is very important
Release time：2018-12-10 Clicks： Click
There are many ways to connect the switch in the circuit. What are the specific ways to connect? Let's give you a detailed introduction.
Diode is used in almost all electronic circuits. It plays an important role in many circuits. It is one of the earliest semiconductor devices. It is also widely used. Crystal diode is a p-n junction formed by p-type semiconductor and n-type semiconductor, and it has two sides at its interface. A space charge layer is formed and a self-built electric field is constructed. When there is no applied voltage, the diffusion current caused by carrier concentration difference on both sides of the p-n junction is equal to the drift current caused by the built-in electric field, so it is in the state of electric equilibrium.
Diodes are used in the switching circuit of the diode in the switching switch. Because the switching speed of the ordinary diode is not high enough, the diode used in this switching circuit is the equivalent circuit of the switching diode for the special switching diode. It can be seen from the figure that the switching diode is equivalent to a switching Sl at this time. At the same time, there are two resistors.
The switch Sl in the equivalent circuit can be considered as an ideal switch, that is, its turn-on resistance is small to zero and its turn-off resistance is large to infinity.
According to the way switching devices are connected in the circuit, the switching power supply which is widely used at present can be generally divided into three categories: series switching power supply, parallel switching power supply and transformer switching power supply.
Among them, transformer switching power supply (hereinafter referred to as transformer switching power supply) can be further divided into push-pull, half-bridge, full-bridge and other types; according to the phase of transformer excitation and output voltage, it can also be divided into forward, flyback, single-excitation and double-excitation.
If the use is divided into more types, it can also be divided into series switching power supply. The disadvantage is that the input and output share the same place. Therefore, EMI interference and charged floor are easy to occur. When the input voltage is the output voltage of the rectifier, it is easy to cause electric shock, which is not safe to the person.