I got a couple of leftover LED strips on a roll that came without a power source, so today, let's figure out how to power them!

► STEPS
1) Check how big are each LED segments. A segment can be identified looking for the signs where the LED can be cut. Between 2 cut signs, here a pair of scissors, is a segment.
2) Look carefully at all the components on 1 segment. In our case, we have 1 segment = 3 x SMD 3528 LED + 1 x 120 Ohm resistor. Note: the resistor is here to limit the current through the segment, avoiding the LED to burn out.
3) Determine the voltage needed to power the LED strip. Each 3528 SMD LED requires around 3 Volts to light up, so 9 Volts total for the 3 LEDs. If we plug it to a 18 volt source, Ohm's law implies that 9 divided by 120 equals 75 mA will travel through the circuit. This is too much for what this type of 3528 LEDs can handle without overheating and prematurely dying. At 12 Volts, the current becomes 25mA which is perfectly fine for what the LEDs are able to handle. 12 volts is therefore a good voltage to provide to this LED strip.
4) Determine the total amperage needed. We know that at 12 Volts, 25 mA will be needed for 1 segment. But the LED strips is made of several segments that will also individually all require 25 mA.
With 27 sections, an LED strip will need at least 27 x 25 equals 675mA. Adding 20% overhead for safety, 810mA is a good choice.
With 16 sections, another LED strip (using the same components per segments) will need at least 16 x 25 equals 400mA, that is a minimum of 480mA including 20% overhead.
5) Determine the appropriate power adapter: Typically, you will not have a power source that matches the exact requirements you have calculated. But as long as you provide the right voltage, and more than the minimal calculated amperage, you will be fine. In my case, an old power adapter from a scanner delivering 12V and 1.25A is perfectly fine!
6) Enjoy the result (after soldering the power adapter wires be careful, polarity matters!!) onto the round copper pads) And the final result? In my case, a safer staircase.

► DISCLAIMER
Always make sure you operate in a safe and secure manner.
Playing with electricity can kill real bad.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
► SUBSCRIBE (weekly content)! http://bit.ly/SubscribeTheLabOtomy
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
► CATCHUP! All Videos http://bit.ly/AllTheLabOtomy
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
▼ CONNECT!
► Facebook: http://bit.ly/CauseIHaveNoFriends
► Twitter: http://bit.ly/LikeASheep
► Instagram: http://bit.ly/NarcissisticByNature
► Tumblr: http://bit.ly/AnotherCatGif
► Pinterest: http://bit.ly/SniffDaMoodBoard
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
▼ MUSIC
► "Sesame Barbarella" by The LabOtomy
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
╔══╦╗╔╦═╦╗╔═╦╗╔═╦══╦═╦╗╔╦╗╔╗
╚╗╔╣╚╝║═╣║║═║╚╣║╠╗╔╣║║╚╝╠╗╔╝
═║║║╔╗║═╣╚╣╦║║║║║║║║║║╠╣║║║═
═╚╝╚╝╚╩═╩═╩╩╩═╩═╝╚╝╚═╩╝╚╝╚╝═