What is a zener diode, how it works and what is used

Stable voltage supply in electronics - this is probably the most important parameter, which is checked without fail. Unfortunately, the stress in our power grids may be changed quite often of the correct value, but to electronic devices were for a long time, it is necessary to ensure a stable power supply, that is, to eliminate all kinds of racing. For these purposes, just used the zener. In this article we will look at them more closely.

What is a zener diode

So, first let's understand what is a zener diode. Zener diode (Zener diode) - a semiconductor diode operating at reverse bias in breakdown mode. Sounds incomprehensible and technical and confusing. To put it simply, the Zener diode is a semiconductor device that stabilizes the voltage. So it sounds more clearly, let's look at how it does it.

How does the zener diode

So, in order to understand the principle of let's imagine the following vessel:

And it should always be maintained in the vessel the same water level. For these purposes, the vessel is made overflow pipe through which resets "excess" fluid, thus maintaining a constant water level. And the overflow begins to operate only when the tube through the filler will be supplied "extra" water.

On exactly the same principle and works zener diode.

Thus, the zener diode operates exclusively in DC voltage, and transmits the forward anode-cathode as a normal diode. But he (zener diode) there is one curious feature, when applying current is not a voltage (cathode-anode) to pass through Zener only as long as the voltage value becomes greater than a predetermined value, which is calculated zener diode.

As seen from the figure above, as soon as the voltage reaches the working region of the zener diode, breakdown occurs therein and current begins to flow through it.

Appearance Zener

old-fashioned Zener (Soviet) produced in an aluminum casing with alphabetic labeling and to determine its denomination, it is necessary to look at the characteristics of a zener diode.

With the foreign models in this respect it is much easier their naminal indicated directly on the unit, and it looks like this:

The main parameters of the zener diode

The main parameters of the Zener diodes are:

1. Voltage. This parameter indicates for what value of the Zener voltage will pass a current in the opposite direction.

2. Current. This value indicates the maximum current that is able to skip the product without breaking down.

Other parameters of the stabilizers are shown in the table below:

Zener diode in the circuit

Now let's put the simplest scheme, which is also called parametric stabilizer.

So let in Scheme applicable D814B zener voltage stabilization 8.9 volts. It turns out to become a zener diode through our current flows in the opposite direction power supply voltage must be greater than the stabilization voltage. In other words, the source should produce 9 volts or more, the stabilizer is opened (earned).

And all the excess will be discharged through the U stabilizer minus. That is, the zener diode - it is our overflow pipe, removes (resets) excess stress (water).

The stabilizer will work correctly as in the voltage ramp, and when it snaps.

If the supply voltage drops below 8.9 volts, the regulator closes and the voltage at the output will also change. Ie no stabilization will not be in principle.

Verifying zener

Check the stabilizer is no different from an ordinary diode check availability and for this we need a multimeter.

Translate to a position continuity multimeter, the red probe leans to the anode and the black lead to the cathode. Thus on the screen of the device should appear palenie direct voltage P-N junction. "1" changing places probes on the display should appear.

These parameters tell the complete health of the zener diode.

We carry out an experiment

So, now let's make a parametric stabilizer scheme D814 D. And begin gradually increase the DC voltage source and when the response threshold see the following:

conclusion

To date, parametric zener gradually give way to a special integral stabilizers and stabilizers from the diodes. But in simple schemes still continue to apply.

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