Banner
Zener diode

Zener diode

Introduction to product description: Zener diode, also known as Zener diode, is different from ordinary diodes. When the Zener diode works in reverse breakdown state, its working current changes in a wide range. The voltage at the end is basically unchanged. Its main function is to obtain a lower output voltage Vo from a higher input voltage Vi. Here we did not describe it like this: Obtain a lower stable output voltage Vo from a higher unstable input voltage Vi. Although the Zener diode has a certain voltage stabilization function, this kind of voltage stabilization ability is not suitable for occasions with high precision requirements. In most practical application circuits, the Zener diode is more to obtain a low precision requirement. High voltage value.

Product Details

product description:

Zener diode, also known as Zener diode, is different from ordinary diodes. When the Zener diode is working in reverse breakdown state, its working current changes in a wide range and the voltage across it is basically not change.

Its main function is to obtain a lower output voltage Vo from a higher input voltage Vi. Here we did not describe it like this: Obtain a lower stable output voltage Vo from a higher unstable input voltage Vi. Although the Zener diode has a certain voltage stabilization function, this kind of voltage stabilization ability is not suitable for occasions with high precision requirements. In most practical application circuits, the Zener diode is more to obtain a low precision requirement. High voltage value.

The gate-source turn-on voltage VGS of the N-channel FET has a maximum limit value, such as ±20V. If this value is exceeded, the FET may damage the ring. Usually in this type of switch control circuit, the VGS value is set to about 10V. If there is only a higher voltage of 36V in the circuit system (others are low voltages such as 5V), this voltage cannot be directly used as the VGS voltage. Of course, you can use a low-dropout linear adjustment chip (LDO) to obtain this voltage from 36V. , But in most cases, we only need the Zener diode as shown in the figure, which has low cost and simple circuit, and this application does not require high voltage regulation accuracy.

Applications:

Typical series voltage regulator circuit

In this circuit, the base of the transistor T is stabilized at 13V by the Zener diode D, and the emitter outputs a constant voltage of 13-0.7=12.3v. Within a certain range, regardless of the increase or decrease of the input voltage and the change of the load resistance, the output The voltage remains the same. This circuit has many uses. The 7805 is a series integrated voltage regulator that can output 5V. The 7805-7824 can output 5-24 volts and is widely used in many electrical appliances. [3]

TV over-voltage protection circuit

115V is the main power supply voltage of the TV. When the output voltage of the power supply is too high, D turns on and t turns on. The collector potential changes from the original high level (5V) to low level, and the TV enters the standby protection state through the voltage of the standby control line

Arc suppression circuit

If a suitable voltage regulating diode is connected in parallel with the inductor (the principle is the same as that of a normal diode), when the coil is cut off in the conducting state, the high voltage generated by the release of electromagnetic energy will be absorbed by the diode, so when the switch is off, the switch will arc Will be eliminated. This application circuit is widely used in industrial fields, such as some high-power electromagnetic control circuits.

Product positive and negative identification:

From the appearance point of view, the positive end of the metal-encapsulated Zener diode body is flat, and the negative end is semicircular. One end of the plastic-encapsulated Zener diode tube with a color mark is the negative electrode, and the other end is the positive electrode. For Zener diodes with unclear signs, you can also use a multimeter to determine the polarity. The measurement method is the same as that of ordinary diodes, that is, use the multimeter R×1k file, connect the two test leads to the two electrodes of the Zener diode, and measure one After the result, adjust the two meter pens to measure. In the two measurement results, the one with the smaller resistance value, the black test lead is connected to the anode of the Zener diode, and the red test lead is connected to the cathode of the Zener diode. This refers to an analog multimeter.

Send Inquiry