The difference between Rectifier Diode and Zener Diode

The difference between Rectifier Diode and Zener Diode.

Crystal diodes are often represented by "D" plus numbers in the circuit, for example: D5 represents the diode numbered 5.
1. Function: the main characteristic of the diode is unidirectional conductivity, that is, under the action of forward voltage, the on resistance is very small, while under the action of reverse voltage, the on resistance is maximum or infinite. Because the diode has the above characteristics, it is often used in rectification, isolation, voltage stabilization, polarity protection, coding control, FM modulation and noise suppression circuits.
The crystal diodes used in telephones can be divided into rectifier diodes (such as 1N4004), isolation diodes (such as 1N4148), Schottky diodes (such as BAT85), light emitting diodes, voltage regulator diodes and so on.
2. Identification method: the identification of the diode is very simple. The N pole (negative pole) of the low power diode is mostly marked by a color circle on the outside of the diode. Some diodes also use the special symbol of the diode to represent the P pole (positive pole) or N pole (negative pole). There are also symbols marked as "P" and "N" to determine the polarity of the diode. The positive and negative electrodes of light-emitting diodes can be identified by the length of the pins, with positive long feet and negative short feet.
3. Points for attention in testing: when using a digital multimeter to measure the diode, the red meter connects the positive pole of the diode and the black meter connects the negative pole of the diode. At this time, the measured resistance value is the positive conduction resistance value of the diode, which is opposite to the pen connection method of the pointer multimeter.
4. The voltage withstand comparison of commonly used 1N4000 series diodes is as follows:
Model 1N4001 1N4002 1N4003 1N4004 1N4005 1N4006 1N4007.
Withstand voltage (V) 50 100 200 400 600 800 1000.
The current (A) is all 1.
Diode: the directional resistance is usually several hundred ohm.
Rectifier diode.
Switching diode: fast reverse recovery, do UHF switch.
Constant current diode: works between the initial voltage and the maximum breakdown voltage, when the current is constant and the dynamic resistance fluctuates greatly; positive operation.
Varactor: junction capacitance is proportional to applied voltage.
Fast recovery diode: reverse breakdown recovery is fast, forward voltage drop is the same as ordinary diode, do intermediate frequency rectifier.
Schottky diode: fast reverse breakdown recovery, small forward voltage drop, high frequency rectifier, detection.
Detection diode: small junction capacitance, large internal resistance, small voltage drop, small forward current, forward operation.
Zener diode: works in the reverse breakdown state, and requires that the current flow is between the maximum current and the stable current, and the dynamic resistance fluctuates little and works in reverse.
Photosensitive diode: the reverse current is proportional to the illumination.