Voltage regulator diode

Zener diode is essentially a special diode, using reverse breakdown characteristics to achieve voltage regulation, so it is called zener diode.

The voltage stabilizer diode uses PN junction reverse breakdown, and the terminal voltage is basically guaranteed to be in a certain range, and the principle of the voltage restorer is the same method .As long as the reverse flow does not exceed the longest working current IZM, the voltage regulating diode will not be damaged.

1.The main parameters of the regulator diode.

( 1 ) Stable voltage Vz:

Stable voltage is the voltage that remains the same at both ends when working normally. Different models have different voltage regulators.

( 2 ) Stable current Iz :

Stable current is the normal operating current in the range of voltage regulation.

( 3 )The maximum stable current

The maximum stable current, is the maximum current that is allowed to be passed over a long period of time. The actual operating current should be less than the IM value, otherwise the regulator tube is easy to burn out.

 ( 4 ) Maximum allowable dissipative power PM

The maximum allowable dissipation power   refers to the maximum allowable value of power consumed by the tube itself when the reverse current is passed through the regulator.

2.Detect the regulator diode

( 1 ) The method of judging an electrode is basically the same as that of judging an ordinary diode electrode. That is, with the multimeter RX1kQ ~ RX10k2 block, first red, black pen arbitrarily connected to the two ends of the voltage regulator, measured a resistance value, and then exchange the stylus and then measured a resistance the resistance value measured twice should be one big and small, the resistance value is smaller, that is, the positive connection method. At this time, the end of the black pen is the positive pole of the voltage stabilizing diode, one end of the red pen is negative.

 ( 2 ) The difference between the voltage regulator diode and the ordinary diode is basically similar to the shape of a common small power rectifier diode. When the model marks on the shell are clear, they can be identified according to the model. When the model symbol is off, the following way can be used to distinguish the voltage regulator diode from the common rectifier diode very accurately.

1）Low Voltage Regulator Diode. First, the positive and negative electrodes of the measured tube are judged by using the multimeter RX 1kQ. Then dial the multimeter to the RX10K2 block, the black stylus is connected to the negative pole of the test tube, the red pen is connected to the positive electrode of the test tube, if the reverse resistance value measured at this time is higher than that of RX1k2 the reverse resistance of the stopper measurement is much smaller. It is explained that the measured tube is a voltage stabilizing tube; on the contrary, if the measured reverse resistance is still very large, it is explained that the tube is a rectifier diode or a detector diode.

2 ) Three-pin Zener Diode and Transistor Distinguish

Three Pin Regulator Diode is a kind of voltage regulator diode with temperature compensation. Its shell contains two levers a voltage stabilizing diode in series with three pins in the same shape as a transistor. One foot and two feet are respectively the negative pole of the two voltage stabilizing diodes, which can be interchanged at will, and one is connected to the positive pole of the power supply when used, and the other is grounded, the 3 pin is the common positive pole of the two voltage regulators, which is suspended in the air.

 The commonly used model is 2DW7, which can be easily identified according to the characteristic of symmetry of 2DW7. First, put the multimeter in RxID or RX100 block, the black stylus connected to the tube of any interest electrode with red pen, in turn, according to the two electric home B10 resistance values are all hundreds ohm and more symmetrical, you can initially conclude that the measured tube is the voltage regulator arm, and the black pen is connected to the center pin then put the multimeter in RX10kQ block, the red pen is connected to 3 feet, and the black stylus contact the other two electrodes in turn, if the resistance is very small and symmetrical, it can be further proved that it is the voltage regulator on the contrary, if measured with RX10 or RX100, 1, 2 feet to 3 feet, although there is a smaller forward electric diode and the RX 10k file repeated measurements without breakdown ( resistance smaller ) phenomenon, that is, but it is not on the tube. Three-pin zener diode is mainly used in the stability of the temperature stability of the circuit.

(3) Regulating value judgment

 Direct read voltage regulator value. In some small voltage regulator diodes, the digital value of the upper is expressed as the voltage regulator, in volts ( V ). For example : 7V5, indicating a voltage regulator value of 7.5V..

But most voltage regulators can not use this method, such as the model is 2CW55, said the voltage regulator is about 8V, such tubes need to check the transistor parameter manual to know.

(4) detection and substitution of voltage stabilized diode

When the diode is damaged, it is difficult to repair. It can only be replaced.

Other models with the same steady voltage value can also be replaced by the common two way tube forward and forward voltage.

This article is from Allicdata Electronics Limited