So I love the fallout series. I love electronics as well. Today I am going to start work on a project. It will be a simple project, but a project none the less. This project has been done before and I take no credit fore the idea, but I am going to make a Nuka Cola Quantum Lamp. This is a simple project that will require a power source (battery), a switch, an led, and a resistor.
So now I am going to describe each element in this circuit.
First lets start out with the LED. Nuka Cola Quantum is blue so naturally we would want to use a blue led. I ordered a grab bag of LEDs off of Sparkfun.com. They don't have the best prices but I like to support them over there. Other places I have bought from are ebay.com and Digikey.com. There are however plenty of other places.
An LED, or Light Emitting Diode, comes in different colors. Just about every color in the rainbow. Each color had a different forward voltage. A forward voltage is the voltage required for the LED to light up. For the bright blue LED the minimum forward voltage is 3.2 volts and the maximum is 3.4 volts at 20mA. This data can be fount on a datasheet. The LED can only handle so much current so we have to add a resistor to limit the current flowing to the LED.
IMPORTANT NOTE: An Led has an anode and a cathode which means that current can only flow in one direction the current must enter the Anode and leave the Cathode. (assuming current leaves from positive to negative)
Here is a basic led circuit similar to the one that I will use.
To determine the resistor value I will derive the equation for finding out the value of the resistor to use in the circuit using KVL. V=6 volts, The forward voltage is 3.2 Volts, and the current is 20milla amps.
so drawing a loop starting above the LED and the current enters the positive terminal of the resistor we get:(Vled is the forward Voltage)
solve for Vresistor
substitute Ohms Law
divide by I(in amps) R=(Vsource-Vled)/I
This is the equation to find the resistor value you need. Not all values are sold in stores however there is a 5% vary in most carbon resistors so you can round to the closest resistor value.
For My project I will use two 3v coin batteries connected in series for a total V source of 6Volts, My led forward voltage is 3.2v and my current needed is 20mA.
So plugging into the formula we get (6-3.2)V/0.020A=140ohms this is not a standard value you could make this by combining resistors in series or parallel but the 150ohm resistor will work just fine for this project.
So I plan on starting construction over the next couple of days and will be posting but I am in the middle of moving so this project is not a top priority. Also just gave you a quick lesson on LED basics :)