The difference between a voltage regulator and an ordinary diode? Characteristics of voltage regulators and their main parameters

The difference between a voltage regulator and an ordinary diode? The characteristics of voltage regulator and its main parameters.

A, the symbol of the voltage regulator

Silicon voltage regulator diode is a silicon diode with PN junction, referred to as voltage regulator. It is used with the appropriate resistance value of the resistor, can play a stable voltage (so that the output voltage of the rectifier circuit can be maintained basically unchanged) role.

Second, the characteristics of the voltage regulator

Ordinary diode in the role of reverse voltage is no current through the (not counting reverse saturation current), such as reverse voltage exceeds the reverse breakdown voltage, the diode will be broken. The opposite is true for voltage regulators, which work in the case of reverse breakdown. From the above figure shows the voltammetric characteristics of the voltage regulator curve can be seen, in the reverse voltage is low, the reverse current is very small, when the reverse voltage reaches or slightly greater than the reverse breakdown voltage, the voltage regulator is breakdown, the reverse current began to increase rapidly. As long as this reverse current does not exceed the limit value of the voltage regulator, outside the voltage cut off, the PN junction can still restore its one-way conductivity. The reverse voltammetric characteristics of the voltage regulator can also be seen in the reverse current changes, the voltage at both ends of the voltage regulator remains almost unchanged.
Third, the main parameters of the voltage regulator

1, stable voltage Uw

Stable voltage is the voltage at both ends of the tube when the voltage regulator works normally. Different voltage stabilizers have different stable voltages.

2, stable current Iw

Stable current is the current value corresponding to the stable voltage on the reverse voltammetric curve, but it is only a reference value to be used as a basis when choosing.

3, the maximum stable current Iwm

When the voltage regulator works, the reverse current exceeds a certain limit, the tube will be bad due to overheating, called thermal breakdown. This limit of the reverse current is the maximum stable current of the voltage regulator.

4, voltage temperature coefficient αv

This is a coefficient used to illustrate the value of the tube voltage regulator affected by temperature changes. Generally, below 6V of the voltage regulator, the temperature coefficient is negative, that is, the temperature (<6V when) lower, Uw also lower; and more than 6V of the voltage regulator, the temperature coefficient is positive, that is, the temperature (>6V when) rise, Uw will also rise. For this reason, to make the voltage of the voltage regulator stable, it is best to choose a tube of about 6V. In the requirement of stable voltage is higher, can also be two or several positive, negative temperature coefficient of the tube in series with, so that they can compensate each other when the temperature changes.

5、Dynamic resistance rw

Dynamic resistance is a parameter that reflects the voltage stabilization performance of the tube, it is equal to the change in voltage at the end of the tube ΔUw and the corresponding current change ΔIw ratio, that is

rw=ΔUw/ΔIw

The smaller the dynamic resistance, the steeper the reverse volt-ampere characteristics, the better the voltage regulator performance of the tube.

Fourth, the difference between the voltage regulator and ordinary diode

1, the voltage regulator works in the reverse breakdown area, ordinary diodes work in the forward work area; voltage regulator reverse breakdown is reversible, when the reverse voltage is removed, the tube and back to normal.

2, the reverse breakdown voltage of the voltage regulator tube is much lower than the ordinary diode.

These differences are caused by the different manufacturing processes.