What type of multimeter is good for testing the quality of LED lamp beads?
The 10k resistor range uses a battery with a voltage of 9-15V. When a large resistor is connected in series, make sure the pointer returns to zero to measure the resistance above 10k.
Because LED beads only light up with a few milliamps of current, when measuring resistance, the small current creates a circuit for the LED light, which performs work and emits light.
By the way, I would like to share a small production: because the battery equipped with this multimeter is not durable, I found two mobile phone batteries connected in series at 8V. This way, the voltage is not enough and the pointer cannot return to zero. So, I changed the resistor and selected a positive type resistor from a large number of resistors. After changing it, it still works well. After using it for a year, I found that the pointer cannot return to zero at 10k gear, indicating that the battery needs to be charged, which is very convenient and convenient.
A digital multimeter can usually measure the quality of LED light beads quickly. Previously, I sent a method of using a multimeter to measure the quality of LED light beads. The diode mode of the multimeter can be used. Nowadays, almost every type of digital multimeter has this mode, so no matter which type of multimeter is used, it can be measured relatively quickly (only for digital, pointer type).
Series connection method
This detection method is also very simple. First, open the lampshade of the LED light to be tested and expose the LED beads. Generally, the LED beads inside are connected in series, so using a diode gear can supply power to this LED bead. If the polarity is not reversed, the normal LED bead will light up, and the damaged LED bead will definitely not light up. Due to the diode gear we choose, the difference in display content between the bad LED bead and the good LED bead can also be clearly displayed on the screen.
Parallel connection method
For the situation where multiple LED chips are connected in parallel, it is possible that the diode mode cannot drive so many LED chips. Therefore, you can try using a 5V power supply with a 330 Ω resistor in the middle, and connect the electrodes to both ends of the LED chips. If you see multiple LED chips lit up and some LED chips not lit up, it can basically be determined that the non lit chip is broken.
Due to the fact that most pointer multimeters use two 1.5V batteries as the power source for the R × 1-R × 1K resistor range, and a 9V laminated battery is used in the R × 10K range, measuring the quality of the LED beads cannot make them emit light normally.
To make LED chips emit light when measuring, a multimeter with a power supply of 4.5V or higher must be selected.
I searched for several multimeters that I had used before for experimental comparison, and in the end, only one multimeter was capable. It is a small portable multimeter powered by a 12V micro battery, with a small size and comprehensive functions. Measuring the quality of LEDs is very intuitive and convenient.
Set the gear to the "on/off" measurement mode, which is also the diode measurement mode. Connect the red probe to the "+" terminal of the LED and the black probe to the "-" terminal to make it light up. It can also be used for online measurement without being affected. Luminous is good, non luminous is bad, very intuitive.
