In the previous part, we have described the little part of LED devices.
Now, we will continue again with them.
We can Divide the LEDs a few groups:
By their color, shape, size and by their manner of montage.
The LEDs can be with a rectangular shape, with a circular or oval shape, with different sizes and diameters. By manner of montage, they divided on trough hole (with leads – pass through the PCB [Printed Circuit Board] ) and SMT ( leadless- Surface Montage Technology) LED devices.
PIC. 1 Large – 10-mm in diameter trough hole diffused
Green LED, 0.1″ – leads pitch
PIC. 2 Mini LEDs RED – for general purpose – battery indicator
1.8mm, 0.1″ – leads pitch
PIC. SMT Rectangular LEDs
When combining many P-N junctions in serial or in parallel , we can create POWER LED. see on a picture below, how looks the 20W Power LED:
PIC. 3 Power LED – 20 Watts
PIC. 4 Dual color, Crystal, 5mm LED (RED+ GREEN)
PIC. 5 Full-color, Crystal, RGB 5mm LED (RED+GREEN+BLUE)
When combining two or three P-N junctions with “the different GaAs saturation of the semiconductor” we get the dual or full color (RGB) LED.
On the picture below you can see the one popular LED member of the ” RGB division “, wide applied into the LED strip applications: RGB-5050.
PIC. 6 Typical Member of RGB division – RGB-5050
VIDEO 1. You can see the different LED kinds
Now, we extend our point of view, and will talk about the LED typical applications. Namely, the LED strips.
In common case, the LED Strips or LED Tapes are thin and flexible PCBs ( 0.2 mm – Printed Circuit Boards )
Used LED devices are leadless -or SMT using devices.
These PCBs can incorporate a single color or a multiple color SMD-LEDs.
The LED tapes or LED strips are characterizing by:
1.) LEDs – single Color:
- Red,Green,Blue,Yellow,White, etc.
2.) Count of LEDs [LEDs per meter]:
- 30, 60, 120 pcs. per meter.
3.) Size (or type – Single Color, RGB colors) of used LEDs:
- SMD2835 – size: 2.8 mm x 3.5 mm;
- SMD3030 – size: 3.0 mm x 3.0 mm;
- SMD3528 – size: 3.5 mm x 2.8 mm;
- SMD4014 – size: 4.0 mm x 1.4 mm;
- SMD5050 – size: 5.0 mm x 5.0 mm;
- SMD5730 – size: 5.7 mm x 3.0 mm.
PIC. 7 SMT Rectangular LEDs – Different Sizes
4.) Powering DC Voltage or Powering AC Voltage.
AC Powering :
- AC 110V
- AC 220V
DC Powering :
- DC5 – DC12V programmable R-G-B cluster
- DC 12V – (“DC 12V are more popular LED Strips” Note By The Author)
- DC 24V.
5.) Maximal Power Consumption – the power dissipated on 1-Meter sized tape or strip.
There are many variants: 4 Watts, 4.8 Watts , 12.2 Watts , 14.4 Watts , etc.
6. ) Efficiency – Lumens per Diode
Example : 5 – 15 lm/ per LED
As we mentioned in the text above, the Tape or Strip is thin and flexible PCB.
Let insert the described SMD LEDS on the desk, and see the PCBoard.
On the picture below, when we look the details, we can see the manufacturer show us a line, with the scissors.
Let We explain: That means the user could cut with the scissors trough this imaginary line, and will get the fully functional piece (Module) of the tape, again working on the same as the label signed working voltage.
Generally, the LED’s module pieces are with 5 cm granularity.
PIC. 9 Typical Single color LED Strips Module – ZOOMED
You can recognize also:
the current limiting resistors: 151 means 150 Ohms – black rectangles,
the line of cutting in black and scissors,
and SMD5050 LEDs – NOW you know what device are at the picture
VIDEO 2. How-to-cut, connect and power LED Strip Lighting
PIC. 10 FULL Color RGB LED Tape In Action
You can see the next Part 3 …