1) Stable voltage Uz

The stable voltage is the operating voltage of the diode in the counter penetration zone, and the voltage at both ends of the tube. This value varies slightly with operating current and temperature. Even for the same type of regulator diode, the stable voltage also has a certain dispersion. For example, the 2CW14 silicon voltage regulator diode has a stable voltage of 6 to 7.5V, and is a direct-plug diode.

2) Temperature coefficient

Temperature change will make VZ change, in the regulator tube, when |VZ|>7V, Vz has a positive temperature coefficient, reverse breakdown is avalanche breakdown. When |Vz|<4V, VZ has a negative temperature coefficient, and the reverse breakdown is Zener breakdown. When 4V<|Vz|<7V, the temperature coefficient of the regulator tube can be close to zero. Such a regulator diode can be used as a standard regulator

3) Stable current Iz

Minimum stable current Izmin, large stable current Izmax Stable current: the reverse current when the operating voltage is equal to the stable voltage; Minimum stable current: the minimum reverse current required for the regulator diode to work at a stable voltage; Maximum stable current: The maximum rental allowed by the reverse curve regulating diode.

The concept of dynamic resistance RZ is the same as that of ordinary diodes, but the dynamic resistance of voltage regulator diodes is derived from their reverse characteristics. The smaller the RZ, the higher the breakdown characteristic of the regulator. RZ = Δ VZ / Δ IZ

4) Dissipated power Pz

When the reverse current passes through the PN junction of the regulator diode, the temperature of the PN junction will also increase, resulting in a certain power loss. The dissipated power of the tube is determined according to the allowable pn junction temperature. Typically, small power tubes are about a few hundred milliwatts to a few watts. Z Large dissipation power Pzm: The Z high power loss of the regulator depends on the area of the PN junction and the heat dissipation conditions. In reverse operation, the power loss of the PN junction is PZ= VZ*IZ, and PZM and VZ can determine IZMAX.

Voltage regulator diodes have been widely used and widely used. It seems that the application is very simple, but if you are not careful, it is also easy to damage. Here are a few things to look for when choosing:

1: Multiple voltage regulator diodes can be used in series, but because the dispersion of the diode parameters is relatively large, it cannot be used in parallel.

2: The pin of the in-line diode must be welded at more than 5mm from the shell, and it is best to use an electric soldering iron below 30W for welding. If 40 ~ 75W electric soldering iron is used for welding, the welding time should not exceed 8 ~ 10s. Try to use internal solder wire welding, do not use bulk solder and rosin method.

3: In order to compensate for the voltage-temperature coefficient of the voltage regulator diode, the voltage regulator diode can be used in series with a silicon diode (including a silicon regulator diode). The series of forward diodes does not exceed three, and can also be used in series with special temperature compensation tubes.

4: Temperature has a great impact on the characteristics of semiconductor devices. When the ambient temperature exceeds 50 ° C, the Z dissipation power should be reduced by 1% for every 1C increase.