The micro LEDs type SMD 0401 SMD 0402, SMD 0603, etc. are very useful if you wish to create small lighting points.
We use them, for example, for wall lights above or on the sides of entrance doors, traffic lights at crossings, locomotive headlights or carriage rear lights, etc. The imagination of every model maker is limitless to use them on a layout.
The dimensions of the smallest LEDs we use are:
- SMD 0401 (L × W × H) : 0.04″ × 0,012″ × 0,02″
- SMD 0402 (L × W × H) : 0.04″ × 0,02″ × 0,02″ in
- SMD 0603 (L × W × H) : 0.025″ × 0.012″ × 0.012″
When you have a soldering iron with a very fine tip and good visual acuity, it is possible to solder wires on SMD 0803, SMD1236 and other SMD LEDs of larger dimensions.
The dimensions are very small and it is almost impossible for a “standard” model maker to solder power leads to these LED’s. Fortunately the sellers offer pre-wired LED’s for sale, which solves the problem.
If you buy pre-wired diodes, it will be useful to secure the solders as they are quite fragile and may break. In this case, it is difficult to solder them again and the LED will be unusable.
To fix this problem, let’s use a simple and relatively effective method :
Twist the two (insulated) wires together very delicately, being careful not to force the welds. This in order that they are in contact.
Apply at the welds (in practice on the LED and on at least 0.4″ of the twisted wires) a drop of cyano. This has the effect of consolidating the Wire / LED bond by reducing or preventing breakage of the solder.
There may be other effective methods that we don’t know about.
If you want to buy and use this type of pre-wired diodes, you will find some from UK sellers – or on eBay (among others) relatively cheaper.
Several types of wires are available depending on the product:
- LED wired with 0.22mm diameter insulated micro-wires, generally the two gray wires. Very fine and very flexible threads.
- LED wired with 0.28mm diameter insulated wires, generally red and black wires. Less discreet and less flexible threads.
- LED wired with uninsulated copper wires. Wires less discreet and less flexible and … not insulated. Watch out for short circuits !
It is up to everyone to determine and choose the product that suits them best.
Feel free to contact us if you wish more information.