ESSENTIAL INFORMATION BUILD INSTRUCTIONS CHECKING YOUR PCB & FAULT-FINDING MECHANICAL DETAILS HOW THE KIT WORKS DESIGN A PRACTICAL DESK LAMP WITH THIS Round 5V LED Desk Lamp Kit Version 1.
LED Desk Lamp Essentials www.kitronik.co.uk/2169 Build Instructions Before you start, take a look at the Printed Circuit Board (PCB). The components go in the side with the writing on and the solder goes on the side with the tracks and silver pads. 1 PLACE THE RESISTORS Start with the resistors R1, R2 and R3. All three are the same so it does not matter which one goes where. It also does not matter which way around they go. Note: Keep the excess leg pieces you have trimmed off.
LED Desk Lamp Essentials www.kitronik.co.uk/2169 Checking Your 5V LED Desk Lamp PCB Is the positive ‘+’ pad on the PCB connected to the positive wire on your 5V power supply? Is the negative ‘-’ pad on the PCB wired to the negative wire on your 5V power supply? Have you soldered all the components in? There should be no unused component holes. Only the four mounting holes should be empty.
LED Desk Lamp Essentials www.kitronik.co.uk/2169 START Power up the board with a connection to a 5V power supply Are any of the LEDs on? NO CHECK Power supply is connected and turned on. Power supply wires are connected the right way around. Resistors R1, R2 and R3 are inserted correctly. Supply links LK1 and LK2 are inserted correctly.
LED Desk Lamp Essentials www.kitronik.co.uk/2169 Adding an On / Off Switch 1 If you wish to add a power switch, cut one of the power wires leading to your 5V LED Desk Lamp PCB. Don’t cut too close to the PCB or it will be difficult to reach the switch. 2 Strip the two ends that were made when you cut the wire. 3 Solder the newly stripped wire to the switch. One piece to each terminal.
LED Desk Lamp Essentials www.kitronik.co.uk/2169 Designing the Enclosure When you design the enclosure, you will need to consider: The size of the PCB (below). Where the power cable comes out. There are four 3.2mm holes in the PCB to secure the PCB in the enclosure. This technical drawing of the built 5V LED Desk Lamp PCB should help you to design your enclosure. The total height of the assembled unit is 9mm.
LED Desk Lamp Essentials www.kitronik.co.uk/2169 How the 5V LED Desk Lamp Works The circuit diagram for the 5V LED Desk Lamp is shown above. It is a very simple circuit. The board contains nine LEDs, these are grouped in threes, with each group of three sharing a current limit resistor. LEDs can be damaged if too much current goes through them, so a 33 Ohm resistor is on each ‘branch’. This allows around 20mA to each LED, or 60mA per branch.
Online Information Two sets of information can be downloaded from the product page where the kit can also be reordered from. The ‘Essential Information’ contains all of the information that you need to get started with the kit and the ‘Teaching Resources’ contains more information on soldering, components used in the kit, educational schemes of work and so on and also includes the essentials. Download from: www.kitronik.co.
