Brief introduction of SMD diode

Crystal diode in the circuit used in "D" and the digital representation, such as: D5 represents the number 5 diode.

1, role: the main characteristics of the diode is unidirectional, i.e. in the forwardunder the action of voltage, on resistance is small; and the conduction resistance significantly or infinite in the role of reverse voltage. Because of the diode with the above-mentioned characteristics, cordless phone often use it in the rectifier,isolation, voltage regulators, polarity protection, code control, frequency modulation and squelch circuit. Phone crystal diode used by function can be divided into: rectifier diodes (such as 1N4004), an isolation diode (such as 1N4148), Schottky diode (such as BAT85), light emitting diodes, zener diode etc..

2, identification method: diode recognition is very simple, small power diode Nelectrode (cathode), in most of the use of a diode appearance color ring mark out,some also use diode diode special symbols to represent the P pole or N pole(Zheng Ji) (negative), but also the use of symbols marked as "P" and "N" to determine the polarity of the diode. The positive and negative pole f-rom the light emitting diode pin length to identify, long legs is positive, negative short feet.

3, test notes: Digital million to measurement of diode with a table, the red pen is connected with the diode cathode, anode black pen is connected with the diode,the resistance of the diode is through resistance, this pointer type multimeter penconnection just the opposite.

4, the commonly used 1N4000 series diode voltage is as follows:

The model 1N4001 1N4002 1N4003 1N4004 1N4005 1N4006 1N4007

Withstand voltage (V) 50100200400600800 1000

Current (A) was 1