What is the function of the diode and how to identify it?

What is the function of the diode and how to identify it?

diodes are very common in circuit applications, and how to use diodes more scientifically in order to make your devices achieve breakthrough improvements, which all need to start with understanding diodes.

1. Role

        The main characteristic of diode is unidirectional conductivity, that is, under the action of forward voltage, the on-resistance is very small; Whereas, under the action of reverse voltage, the on-resistance is very large or infinite.

       diode are divided into crystal diodes, bidirectional trigger diodes, high-frequency varistor diodes, varactor diodes, generating diodes, and Schottky diodes according to their uses.

2. Identification method

         The identification of the diode is very simple, the N pole (negative pole) of the low-power diode, most of the diodes are marked with a color circle in the diode table, and some diodes are also marked with diode-specific symbols as "P" and "N" to determine the polarity of the diode.

The positive and negative poles of a light-emitting diode can be identified by the length of the pins, with the long pins being positive and the short pins being negative.

3. Test precautions

       When measuring the diode with a digital multimeter, the red pen is connected to the positive pole of the diode, and the black pen is connected to the negative pole of the diode, and the resistance value obtained at this time is the forward conduction resistance value of the diode, which is just the opposite of the pen connection method of the pointer multimeter.

4. Fault characteristics

       The faults of diode are mainly manifested in open circuits, short circuits and unstable voltage regulation. Of these three faults, the former one exhibits an increase in the supply voltage; Worries are manifested in the form of the power supply voltage falling to zero volts or the output being unstable.