LED lamp beads, in fact, is a light-emitting diodes, load a certain voltage and current will be light. Generally speaking, the voltage of a single led chip in the 3V or so, the current in the 30mA this way, and for the LED lamp beads voltage and current, mostly LED packaging process, LED chip series and parallel relationship between the decision.
Lamp with the most used 0.2W LED lamp beads, is two LED chips in parallel, that is, 3V, 60MA. And for the resistance of the power supply with the most high-voltage LED 9V lamp beads, it is made of three LED chips in series, that is, 9V, 30MA.
Because LED lamp beads are made up of multiple LED chips in series, so the LED lamp beads specifications can have a lot of voltage can also have a variety of. The specific lamp beads is how much service, you can also see how many LED chips are composed of LED chips, of course, because the LED chip is relatively small, wire bonding wire is also relatively small, visual only probably estimate, specifically or Want to use the DC source to know.
But also used more or 3V, 6V, 9V, etc., of course, there are dozens of V lamp beads, this depends on the specific design to really what kind of lamp beads.
For only 3V lamp beads, you can use the multimeter die to light this lamp beads, but there are positive and negative, not bright on the change of positive and negative on the line. For the LED lamp beads that do not know the voltage, it can only use the DC source to measure, the method is: the DC source voltage zero, the current transferred to the maximum, then the lamp beads positive and negative, adjust the current source voltage From zero to become larger, to the lamp beads light, when the voltage on the LED lamp beads about the voltage.
For COB lamp beads, in fact, is a principle, but COB package more LED chips, voltage and current will be relatively large. The COB lamp beads voltage and current confirmation method is also used to confirm the DC source.
Use DC source to confirm this is the most simple and crude method, in the development process of the most applications, copy the lights of others, but also to confirm the use of other people with the lamp beads specifications.
Each type of lamp beads has its own characteristics, some cost-effective, and some better performance. And each manufacturer with the specifications of the LED lamp beads will be different, so the LED lamp beads are not absolutely good or bad, as long as the use of good will play his greatest role.