1. Circuit design of LED strip
The circuit of the LED light strip includes series circuit and parallel circuit, as well as series-parallel circuit.
a. The advantage of the series circuit is that the current is constant and it is easier to control the driving current of the LED. The disadvantage is that if one of the LEDs is damaged, all the LEDs will not light up, but it will not affect the life of the other LEDs.
b. The advantage of the parallel circuit is that any LED failure will not affect the use of other LEDs. The disadvantage is that if no current-limiting resistor is added, any one of the LEDs will be damaged, which will cause the current at both ends of the other LEDs to increase, which will burn the other LEDs. And because the driving voltage of a single LED is very low, it will cause most of the voltage to do useless work, which is also a waste of resources.
c. The series-parallel circuit is a common circuit for LED strips at present, because several LEDs are connected in series to form a group, and then connected in parallel with other groups. It can greatly increase the utilization rate of the power supply voltage and reduce the loss of useless power. At the same time, the use of several LEDs in series can ensure that the driving currents of these LEDs are consistent, which is conducive to constant LED currents to ensure the service life of the LEDs. The series-connected LED lamp group is then connected in parallel with other groups to ensure that if one group is damaged, it will not affect the normal use of other groups. At the same time, since each group has a current-limiting resistor, the service life of the other groups will not be affected by the damage of one group.
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2. The number of LED lamp beads per meter
Under normal circumstances, the number of LED lights per meter is fixed. For example, the 1210 has 60 lights, the 5050 has 30 lights, and the special one has 60 lights. If there are other special requirements, such as 50 lights per meter, this involves modifying the circuit. Because it is usually a group of 3 LEDs, if it is 50 lights, there will be a group that is not enough, but if it is a group of two LEDs, the resistance of the current limiting resistor will be increased, which will cause a waste of resources . Therefore, when making customized LED strips with special requirements, you must pay attention to the number of lamp beads is a multiple of 3, so as not to cause a waste of voltage resources.