## How to measure the quality of led driver with multimeter, and how to measure the quality of LED driver chip with multimeter?

The voltage of non-isolated LED power supply under no-load condition is about 300V tested by multimeter and about 220V with current-by-current PFC. The isolated LED power supply, the voltage in the no-load state is tested with a multimeter, and the total voltage is about 3-5V more than the rated number of LED series.

It is impossible to measure the quality of LED with ordinary pointer multimeter, because the working voltage of LED is about 7V, while the internal voltage of ordinary pointer multimeter is only 5V, so when measuring LED with the resistance file of ordinary multimeter, its forward and reverse resistance is infinite.

I don’t know if you are talking about LED display unit board or full-color LED driver chip. Generally, you can compare the voltage of the same pin of the normal driver chip, the resistance parameters, and the on-off test to see if the short circuit, short circuit. The most important thing is to be familiar with the function and routing mode of each driver chip on the unit board.

## How to check the quality of LED driver with Multimeter

Use a multimeter to measure the output voltage of the driver. If the value of the test is the same as that marked on it, the driver is good. Otherwise, the drive is broken. The performance of a broken led drive.

Turn the knob on the multimeter to the diode (buzzing) file and insert the red and black pen in the correct position of the multimeter. Observation lamp, there are four-legged and two-legged, if the measurement is four-legged, the middle two feet are selected.

It is impossible to measure the quality of LED with ordinary pointer multimeter, because the working voltage of LED is about 7V, while the internal voltage of ordinary pointer multimeter is only 5V, so when measuring LED with the resistance file of ordinary multimeter, its forward and reverse resistance is infinite.

The multimeter can not be measured, so we can only simply test whether the input and output are short-circuited. If it is the simplest resistance-capacitance constant current source, you can test whether the capacitor is short-circuited, as long as the capacitor is not short-circuited, connected to the led lamp string, the power will be on.

## How to measure the quality of LED lamp by multimeter

1. The red pen of the multimeter is in contact with the anode contact body of the lamp, and the black pen of the multimeter is in contact with the cathode contact body. See if the lights are on. If the light is on, it means that the function of the lamp bead is basically all right. If the lamp is not lit, swap the red and black watch pen and test it again. Lest the cathode and anode of some lamp beads are opposite to the general ones.

2, the multimeter measures the quality of LED lamp beads in the following ways: 1, the multimeter chooses the diode file, the red meter pen connects the lamp bead anode, the black meter pen connects the lamp bead cathode, if the lamp bead is slightly bright, it is good, otherwise it is bad. 2, the multimeter selects * 10k resistance file, the red meter pen connects with the lamp bead anode, the black meter pen connects with the cathode, the lamp bead is slightly bright is good.

3. A, use a universal red pen to connect the positive contact of the LED lamp bead, and use a universal meter black pen to connect the negative contact. When the LED lamp bead has a small brightness, it is good, otherwise it may be bad.

4, you can also use the diode file of the digital multimeter to measure the quality of the LED, the red meter is connected with the positive pole of LED, and the black meter is connected with the negative pole of LED. At this time, the digital multimeter displays around 1700, and the reverse measurement will be infinity. It shows that “1Muffle, which can basically prove that LED is good.”

5. Use the diode gear of the multimeter to measure, the red meter pen connected to the positive pole of the LED lamp, and the black meter pen connected to the negative pole, which shows that the LED lamp is good, otherwise it is bad.

6. Because the resistance test voltage of some pointer multimeters is too low, it may not be able to light the LED, so if the resistor range can not light the LED, you can try to connect a dry cell in series and test again.