The difference between 1N4148 and 1N5819: high frequency, low voltage and high current characteristics are the differences between 1N5819 diodes and ordinary diodes. It is widely used in switching power supplies, inverters, drivers and other circuits for high frequency, low voltage, and high current rectification. Current and protection diodes are used. 1N5819 is characterized by ultra-fast speed (low switching loss), extremely low voltage drop (low voltage loss), but also low withstand voltage, usually less than 60V, suitable for low-voltage (<=12V) switching power supplies. Ordinary diode fast recovery speed, large voltage drop, high withstand voltage, suitable for high voltage (>12V~1000V) switching power supply. 1N4148 is a point contact type small current rectifier, with high speed, but the current is only 50mA. Another use of 1N5819 diode is to stabilize voltage-use reverse characteristics. Therefore, when the withstand voltage is low and the current is not large, you can consider using a Zener tube instead. The reverse leakage of the 1N5819 tube is a bit larger. But the capacitance is small. high speed. But it is not as fast as 1N4148, after all, the purpose of others is high frequency detection, not rectification.

The difference between 1N4148 and 1N4007: 1N4148 and 1N4007 in general small current (below 100mA, reverse voltage below 100V), and can be replaced in an emergency. 1N4148 is a small current switch tube, 100V withstand voltage, 1N4007 is a rectifier tube, 1A- 1000V. There are many types of substitute models

1. Rectifier diode: The unidirectional conductivity of the diode can be used to transform alternating current with alternating directions into pulsating direct current in a single direction.

2. Detector diode: a device that detects the low-beard signal superimposed on the high-frequency rewave. It has a higher detection frequency and good frequency characteristics, and it plays a role in the detection of the radio.

3. Switching diode: Since the on-resistance of semiconductor diodes is very small under forward bias, and when reverse bias is applied, the off-resistance is very large. The unidirectional conductivity of semiconductor diodes is used in switching circuits It can turn on and off the current.

4. Zener diode: Zener diode, also known as Zener diode, uses the characteristic that the voltage basically does not change with the current change during the reverse breakdown of the PN junction to achieve the purpose of voltage stabilization, so it plays a role in the circuit The role is to stabilize.

5. Fast recovery diode (FRD): This is a new type of semiconductor diode with good switching characteristics and short reverse recovery time. It is often used as a rectifier diode in high-frequency switching power supplies. The rectifier diodes of color TVs and other household appliances that use switching power supplies are usually such diodes instead of ordinary rectifier diodes, otherwise the electrical appliances may not work normally.

6. Schottky diode (SBD): Schottky diode, also known as Schottky barrier diode, or SBD for short, is a low-power, high-current, ultra-high-speed semiconductor device. Its reverse recovery time is extremely short (can be as small as a few nanoseconds), the forward voltage drop is only about 0.4V, and the rectified current can reach several thousand amperes. These excellent characteristics are unmatched by fast recovery diodes.

7. Transient voltage suppression diode: TVS tube for short, is a semiconductor device developed on the basis of the technology of voltage regulator tube. When the voltage at both ends is higher than the rated value, it will be turned on instantaneously, and the resistance at both ends will change from high resistance to low resistance at a very high speed, thereby absorbing a very large current and clamping the voltage at both ends of the tube. On the predetermined value. This type of diode is mainly used in fast overvoltage protection circuits.

8. Light-emitting diode: LED for short in English is made of semiconductor materials such as phosphatizer and phosphorous gallium arsenide. In addition to the unidirectional conductivity of this type of diode, it can also convert electrical energy into light energy. The color of the light is mainly determined by the material used to make the tube and the type of impurities involved. At present, the main colors are blue, green, yellow, red, orange, and white.

9. Avalanche diode: Avalanche diode is a kind of microwave power device developed in Zener tube technology. It can produce high frequency oscillation under the action of applied voltage. Long used in microwave communications, radar, tactical missiles, remote control, telemetry and other equipment.

10. Bidirectional trigger diode: Bidirectional trigger diode, also known as two-terminal AC device (DIAC), is a silicon bidirectional voltage trigger switch device. When the voltage applied across the bidirectional trigger diode exceeds its breakdown voltage, it will be turned on, and the turn on will continue until the current is interrupted or it drops to the minimum holding current of the device before it can be turned off again. Such diodes are usually used in overvoltage protection circuits, phase shift circuits, thyristor trigger circuits, and timing circuits.

11. Variable capacitance diode: variable capacitance diode, or VCD for short, is a special semiconductor device that uses reverse bias to change the capacitance of the PN junction. It is equivalent to a variable-capacity capacitor, and the PN junction capacitance between its two electrodes changes with the change of the reverse voltage applied to both ends of the varactor diode. This type of diode is mainly used in color TV tuning circuits (such as color TV tuner), as an automatic fine-tuning capacitor that can be controlled.