At present, the high-pressure sodium lamps and low-pressure sodium lamps commonly used in the public power street lamp industry in my country, the reason why they choose to use sodium lamps is because they have the characteristics of high light efficiency and long life. Take a high-pressure sodium lamp as an example: the light efficiency is 120lm/w, and the average life span can reach 2 years. But it also has its own significant defects, that is, the color temperature (K=1900/2200/2500) is too low, and the color rendering index (Ra=23 /60) is too poor. In order to solve the problem of low color temperature and serious reddish color of high-pressure sodium lamps, the commonly used method is to increase the power, so that the power can reach 250-400W and use a super luminous flux value to compensate for the color cast of the object. The average illuminance value required by the national standard JT/T367-1997 "Technical Conditions of Highway Lighting" is 15LX in most cases and does not require high luminous flux. This means that in many cases, it is not necessary to use sodium lamps with such high power and high luminous flux to illuminate, but because of the low luminous flux, all objects under the lamp will be severely discolored, generally become yellowish.
1.Electronic transformer step-down: The disadvantage of this power supply layout is low conversion power and narrow voltage scale, usually 180~240V, with large ripple disturbance. 2. Capacitor step-down: The LED waterproof power supply of this method is simply affected by the fluctuation of the grid voltage, and the power of the power supply is low, so it is not suitable for the LED to be used when flashing. Because the circuit is stepped down by the capacitor, during the flashing operation, due to the effect of charging and discharging, the instantaneous current passing through the LED is extremely large, which simply damages the chip. 3. PWM controlled switching power supply: the output voltage or current of this LED waterproof power supply is very stable.
The LED power supply is a type of power supply. It is a device that provides power to electronic equipment, also called a power supply. It is deployed as a device with different power inputs connected to independent circuit equipment with two or three power inputs. According to the power supply voltage, it can be divided into high-voltage 85-265V and low-voltage 12-80V; currently commonly used outdoor power supplies use high-voltage driving power, such as: street lights, flood lights, track lights, underground lights, corn lights; and general Indoor lighting gradually adopts low-voltage drive, such as spotlights, candle lights, panel lights, ceiling lights, bulb lights, and fluorescent lights. According to the power supply characteristics, it can be divided into constant current power supply and constant voltage power supply; constant voltage power supply is mainly used for switching power supply, power adapter, and constant current power supply is mainly used for various lighting, such as street lights, panel lights, flood lights, garden lights , Candle lights, fluorescent lights, ceiling lights, panel lights, spotlights; and automotive LEDs, LED drivers for electric vehicles, etc.
Theoretically: Constant voltage means that no matter how the load changes, the output voltage of the power supply will not change. The constant current means that no matter how the load changes, the current output by the power supply will not change. To achieve constant voltage, the internal resistance of the power supply is required to be infinitely small. No matter how the loop current changes due to the size of the external load, there will be no voltage drop caused by the internal resistance of the power supply, so as to ensure that the power output of the power supply is constant, but to achieve constant current. It means that the internal resistance of the power supply is infinite. No matter how the external load changes and the loop resistance changes, the relatively infinite power supply internal resistance will not cause any change in the impedance on the loop, and the constant current power supply will be obtained by coincidence.
LED drive power potting glue is suitable for potting protection of general electronic components, power modules and circuit boards, as well as potting of various electronic appliances, such as switching power supplies, driving power supplies, automotive HID lamp module power supplies, and automotive ignition system module power supplies , Home appliance controllers, network transformers, etc. Many customers don’t know much about the operation method of the LED driver power potting glue, so that the cured main agent is too soft or the surface is too sticky.