The difference between rectifier diode and voltage regulator diode

The difference between rectifier diode and voltage regulator diode

Crystal diodes are commonly indicated by "D" and numbers in circuits, such as D5 indicating the diode with number 5.

1. Effect: The primary characteristic of a diode is its single conductor conductivity, which means that under the effect of forward voltage, the conduction resistance is very small; Under the reverse voltage effect, the conduction resistance is extremely large or infinite. Because of the above characteristics of diodes, cordless telephones often use them in circuits such as rectification, barrier, voltage stabilization, polarity maintenance, coding control, frequency modulation and noise suppression.

The crystal diodes used in telephones can be divided into rectifier diode (such as 1N4004), barrier diodes (such as 1N4148), Schottky diodes (such as BAT85), light emitting diodes, voltage stabilizing diodes, etc. according to their effects.

2. Identification method: The identification of diodes is very simple. The N-pole (negative pole) of low-power diodes is mostly marked with a color circle on the surface of the diode. Some diodes also use diode specific symbols to indicate the P-pole (positive pole) or N-pole (negative pole), and some use symbols marked with "P" or "N" to determine the polarity of the diode. The positive and negative poles of a light-emitting diode can be identified by the length of the pins, with the long pin being positive and the short pin being negative.

3. Test precautions: When using a digital multimeter to measure a diode, the red lead is connected to the positive pole of the diode, and the black lead is connected to the negative pole of the diode. At this time, the measured resistance value is the positive conduction resistance value of the diode, which is exactly the opposite of the probe connection method of a pointer type multimeter.

4. The commonly used 1N4000 series diodes have the following voltage withstand comparison:

Type 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 characteristic resistance is generally several hundred ohms

rectifier diode

Switch diode: fast reverse recovery, Super high frequency switch

Constant current diode: The operation is between the starting voltage and the Z high breakdown voltage, during which the current remains constant and the dynamic resistance fluctuates greatly; Forward operation

Varactor diode: The junction capacitance is proportional to the applied voltage

Fast recovery diode: reverse breakdown recovery is fast, and the forward voltage drop is the same as that of ordinary diodes, performing intermediate frequency rectification

Schottky diode: fast reverse breakdown recovery, small forward voltage drop, high-frequency rectification, detection

Detector diode: small junction capacitance, large internal resistance, low voltage drop, low forward current, forward operation

rectifier diode Voltage regulator diode: When operating in reverse breakdown state, the current flowing through it is required to be between Z large current and stable current, and the dynamic resistance fluctuates slightly, resulting in reverse operation

Photodiode: The reverse current is linearly proportional to the illumination. Assignment and Reverse