I've gotten big into electronics recently and boy have I got some fun experiments you can try at home.
Before we get started, you must learn a simple formula called Ohms Law:
...Yikes too complex. How bout a simple triangle:
Thats better. V = Volts. I = Current (measured in amps or milliamps). And R = Resistance (measured in Ohms).
Look at the triangle harder. Notice something? Look again.
V = I * R
I = V / R
R = V / I
It's very simple. And I shown you this for a reason. This will help you in the world of electronics. And you can nearly obtain everything you need at any Radio Shack or other electronics supplier. Electronics are like programming. You experiment with it until something works. For an easy first timer experiment you'll need:
- 9v battery
- Various lengths and colors of alligator clips
- LED light of any color you desire
- Resistors of various Ohms
You'll notice the battery has a (+) end which is a cylinder in shape and a (-) end which is a cup shape.
What's a resistor? Funny you should ask. Resistors are as the name goes. It resists the amount of voltage directly put into it and has less voltage coming out of it as a result. This comes in handy for when using devices that only requires a little voltage. If too much voltage is going through the device directly without the resistor, you can easily damage and destroy the device. Resistors are color coded to show the amount of resistance in Ohms.
5% +/- Tolerance -> Gold
10% +/- Tolerance -> Silver
20% +/- Tolerance -> None
There are typically 4 colors on the resistor. The first 2 are the values. The 3rd color is the multiplier. The 4th color is the tolerance. So lets say you have Red Red Brown Gold:
Red = 2
Red = 2
Brown = 10^1
Gold = 5% +/- Tolerance
= 22 * 10^1
= 220 Ohms with a 5% +/- Tolerance
Now that you know resistors. Lets get started!
Step 1) Depending on the color LED you choose will depend on the resistor required. Lets take a white LED. The forward current is 25 mA (0.025 amps). The forward voltage of this LED is 3.3V. Lets do some math. We are using a 9 volt battery here. So if we wanted to find the resistance required:
R = V / I
Voltage is actually broken up into 2 parts. The supply voltage (battery or other power source) and forward voltage (your devices voltage). So the formula is now this:
R = (Vs - Vf) / I
Note: If using more than one LED light, you will need to add more forward voltage by adding the total forward voltage values such as in this formula:
R = (Vs - (Vf1 + Vf2 +...)) / I
Now lets input some values. The LED light has a 3.3v forward voltage as mentioned above, and we are using a 9v battery for source voltage.
R = (9v - 3.3v) / 0.025 A = 228 Ohms
The nearest available resistor for this is in fact 220 Ohms! (Red Red Brown = 220) So well be using a 220 Ohm resistor.
Step 2) Connect the Red alligator clip to the (+) positive end of the battery. Connect the other end of the Red alligator clip to the 220 Ohm resistor. The resistor has no polarity so either end of the resistor is fine.
Step 3) Connect any color alligator clip you choose to the other end of the resistor. In my case I chose white to avoid confusion. Then connect the other white end of the alligator clip to the LED lights long end (+) positive. The short end by the way is (-) negative and is also known as ground.
Step 4) Connect a Black alligator clip to the short end of the LED which is (-) negative and connect the other end of the black clip to the (-) negative end of the battery.
Step 5) It should light up. If it didn't. You messed something up. Retrace your steps and try again.
This is basically your Hello World version of electronics. I will have more fun experiments in the near future. Coming up next! Using a potentiameter as a dimmer switch for your LED!