Basic knowledge and application of plug-in diodes

The main parameters of diodes: forward current, forward voltage drop, reverse breakdown voltage, reverse leakage current, junction capacitance, etc.

The main characteristics of the diode: forward conduction, reverse cutoff.

The main role of the diode: rectification, voltage regulation, renewal, amplitude detection, switching, luminescence, etc.

Classification of plug-in diodes:

1, according to the installation method: SMD and plug-in, they are different: A SMD diode available SMD machine to paste the components on the PCB, can also be manually soldered on the PCB with a soldering iron, the type of SMD according to the size of the current, package sizes vary such as: LL34, LL41, SOD123, SOD323, SOD523, DO-213AA, DO214-AC SMA, SOT23, etc., B plug-in diode either manual welding, or first inserted in the circuit board and then fixed on the PCB through wave soldering, plug-in size also varies according to the size of the current, such as: DO-35, DO-41, TO-220, etc., in the design point of view, if the space and function to meet the premise, the preferred choice of SMD components to reduce product costs.

2, the type of diode: A, working in the forward conduction state such as: ordinary rectifier diode, ultra-fast recovery diode, Schottky diode, light-emitting diode, etc., B, working in the reverse breakdown state such as: voltage regulator diode TVS tube (transient suppression diode), etc.

3, the choice of diode: A, ordinary rectifier diode due to low response speed, flow through the current can be made very large, reverse voltage is very large, generally applicable to low frequency high current high voltage rectifier circuit (50HZ/60HZ). B, ultra-fast recovery diode due to fast response speed. Large current. Reverse voltage is large, mostly used in high voltage, high frequency. C, Schottky diode, low power consumption. Fast. High current. Reverse withstand voltage is slightly lower than in the switching power supply output rectification and renewal circuit. d, voltage regulator used to stabilize the voltage at a certain point, and TVS is mainly used as a circuit transient shock protection, fast response time, strong carrying capacity.

4, diode selection: mainly according to the circuit characteristics such as: voltage. Frequency . Current. Working environment to select the appropriate components.

5, the plug-in diode measurement: multimeter is only a simple good and bad measurement: such as multimeter dial to plug-in diode measurement file, with the meter head to touch the diode ends, respectively, the meter head forward connection, will show a value, reverse connection no value, if you want to test the specific parameters have to use special instruments, many companies do not have such conditions, so we have to choose the brand and choose quality when selecting the type suppliers.