Zener diodes work with the voltage stabilization characteristics of multiple areas of reverse impact, so Zener diodes should be connected in the reverse direction in the circuit. The reverse breakdown voltage of a Zener diode is called a stable voltage, and different types of Zener diodes have different stable voltages. The stable voltage of a certain Zener diode is fixed within a fixed range. For example, the adjustment value of 2CW11 is 3.2v to 4.5v, the adjustment value of one pipe can be 3.5v, and the adjustment value of the other pipe can be 4.2v.
In practical applications, if you can’t choose a zener diode with a lower voltage stabilization value, you can choose a zener diode with a lower voltage stabilization value, and then connect one or more silicon diodes in series to the "pillow cushion" to increase the stable voltage To the desired value. This uses the forward voltage drop of the silicon diode to stabilize the voltage. Therefore, the diode must be connected forward in the circuit, which is different from the Zener diode.
The voltage stabilization performance of a Zener diode can be expressed by its dynamic resistance r: Obviously, for the same current change δ1, the smaller the voltage change δU across the Zener diode, the smaller the dynamic resistance, and the better the performance of the Zener diode. . The dynamic resistance of the Zener diode changes with the operating current, the greater the operating current. The smaller the dynamic resistance. Therefore, in order to achieve a good voltage stabilization effect, the operating current should be appropriately selected. If you choose a larger operating current, you can reduce the dynamic resistance, but it cannot exceed the maximum allowable current (or maximum power dissipation) of the tube.
The stability of Zener diode is affected by temperature. When the temperature changes, its stable voltage also changes. The temperature coefficient of a stable voltage is usually used to express this performance. For example, the stable voltage UW of the 2CW19 Zener diode is 12 volts and the temperature coefficient is 0.095% ℃, which means that for every 1 ℃ increase in temperature, the stable voltage increases by 11.4 millivolts. In order to improve the stability of the circuit, appropriate temperature compensation measures are usually adopted. When the stability performance is very high, the voltage stabilization method with temperature compensation should be adopted, such as 2DW7A, 2DW7W, 2DW7C, etc.
The above explained is the basic introduction and principle of Zener diodes. I hope it will be helpful to you after reading. If you want to know more about Zener diodes, please contact customer service online or call our company. Service hotline (upper right corner of the website) for consultation, we will wholeheartedly provide you with quality service!