Diode is a semiconductor device that allows electricity to flow in one direction and it is used in all kinds of circuits. It is common but it is not original. What functions does diode has to meet the requirements of different circuits? The following passage will tell you.

　　Rectifying

　　The first function of diode is rectifying. Those diodes that can rectify the current are called rectifier. Due to its one-direction current flow, diodes can change the alternating current to pulse direct current.

　　Limiting

　　The second function is limiting. Limiting diode is a device that can finish limiting in circuit. When forward voltage is added on both electrodes to conduct the diode, the forward voltage drop would remain constant. Hence, limiting diode can be used as limiting component to restrict signals within certain ranges.

　　Switching

　　The third function is switching. The resistance is low under forward voltage, which can be seen as closed circuit, and it is similar to the turn-on of a switch. On the contrary, resistance becomes high under reverse voltage, equivalence to broken circuit, and it is similar to the turn-off of a switch. This kind of feature enables diodes to form all types of logic circuits.

　　Freewheeling

　　The fourth function is freewheeling. Freewheeling diode is usually used in induction of switching mode power supply or inductive load of electronic relay.

　　Voltage regulating

　　The fifth function is voltage regulating. Zener diode is a junction silicon diode that works on reverse breakdown state. Inserting a current limiting resistance into a voltage stabilizing circuit to restrict the current after breakdown of zener diode so as this state of breakdown could last in the circuit.

　　Capacity changing

　　The sixth function is capacity changing. The static capacity on PN junction could be changed by adding reverse voltage on varactor which is often applied in high frequency turner of a TV machine.

　　Screening

　　The seventh function is screening. The diodes that emit light is called LED and they are widely used in VCD, DVD, computer display, for example, the lights on computer disk and cell phone charger are given out by LED.

　　Triggering

　　Triggering is the eighth function of a diode. The trigger diode, also called bidirectional DIAC, is a symmetrical semiconductor device used to control the triac and protection for overvoltage.

　　Detecting

　　Detection is the ninth function. A radio would use detection to check out the low frequency signals among the high frequency signals.

　　The above are some functions of diodes. If you are interested in diode and want to know more, please visit our website: www.huixinelec.com