LED beads, in fact, is an aluminous diode, loaded with a certain voltage, and current will emit light. Usually, a single LED chip has a voltage of about 3V and a current of 30mA. The voltage and current of LED beads are mostly determined by the series-parallel relationship of LED chips in the process of an LED package.
The most used 0.2W LED beads in the light tube are two LED chips in parallel, namely 3V, 60MA. While the high-voltage LED 9V light beads, which are most used in resistor-capacitor power supply, three LED chips are connected in series, namely 9V, 30MA. Because LED beads are made of several LED chips in series and in parallel, there are many kinds of specifications for LED beads. Shenzhen Crescent EMC3030 SMD LED
voltage can also be varaious. You can also see how many LED chips the beads are made up of to see that specific number of beads is V.Of course, because the LED chip is relatively small, and the gold wire bonded by the lead is relatively small, too, visual measurement can only be estimated roughly, or the specific use of DC source measurement to know. However, 3V, 6V, 9V and so on are still used most, of course, there are dozens of V beads, depending on the specific design to use.
For a 3 V bulb, the diode gear of the multimeter can be used to light the bulb. This one has positive and negative poles. If it's not bright, just change the positive and negative. For LED beads with unknown voltage, it can only be measured by DC current. The method is to adjust the DC current voltage to zero and make the current to the maximum. Connect the positive and negative poles of the light beads, then adjust the voltage of the minimum current to make it larger from zero. When the light beads are light, the voltage at this time is the approximate voltage of the LED light beads.
For COB beads, it is also the same principle. The only difference is that the COB LED package
more chips, the voltage and current will be relatively large. And the method of confirming the voltage and current of COB light beads is also confirmed by DC current. It is the simplest and rudest method to use DC current to confirm. This method is used most in the development process. When plagiarizing other people's lamp, it is the same way to confirm the specifications of other people's light beads.
Each specification of light beads has its own characteristics. Some have a higher cost-effective ratio and some have a better performance. And one manufacturer will also have different LED beads of the same specification. So LED beads are not absolutely standing or falling. As long as they are used well, they will play their greatest role.