Fun With Electricity-VBForums

1. ## Fun With Electricity

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.

0) Black
1) Brown
2) Red
3) Orange
4) Yellow
5) Green
6) Blue
7) Violet
8) Gray
9) White

5&#37; +/- 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!

2. ## Re: Fun With Electricity

The E in E=IR stands for "electromotive force" though the I is more mysterious. Many people claim it came from "intensity" but I have my doubts about that.

E is measured in Volts, I in Amps, and R in Ohms.

"V=IR" is sort of "hillbilly eletricity" as far as I know. Using it as a test answer would surely get you marked down. You might as well say "V=AO" if you're going to write that.

3. ## Re: Fun With Electricity

We did loads of electricity related work last year and this is how I learned most of the formulas:
using triangles like the one that you posted above.
V = IR
Q = IT
W = VQ
If you put those in triangles like the one jacob posted then you have most of the general formulas.

4. ## Re: Fun With Electricity

You might have gone on to discuss some of the more significant points about resistance. After all, electrical resistance is very useful. Force enough electricity through a resistor, and the resistor will heat up. That heat has some value. For instance, you can shape the resistor into a coil and use it to heat the water. Have a few of those arranged in a flat coil and you can heat a pot of soup. That should be familiar to everybody. Furthermore, you can use a simple meter to measure that resistance. In other words, you can really see whether you have an Ohm on the range.

You could also talk about varistors, which are resistors with varying amounts of resistance (usually set using a dial, or often a screw for small varistors). The ability of varistors to alter the resistance in a circuit has found many uses when it comes to creating a linnear control, such as volume, or heat controls, or the like. It isn't the only alternative, but it is a really simple one, and frequently used. Therefore, the next time you turn down the stereo, you can think of it as a kind of Ohm improvement project.

5. ## Re: Fun With Electricity

Er... http://en.wikipedia.org/wiki/Varistor

I think you mean potentiometer or rheostat instead.

6. ## Re: Fun With Electricity

So I should have said potentiometer or rheostat, according to wiki. It certainly wouldn't have affected the pun in any way (and that was the whole purpose of the statement, of course), but I have heard varistor used in ways that are not consistent with what wiki states. What a surprise!!

7. ## Re: Fun With Electricity

It's strange... I always thought that a resistor resists the current, the voltage stays the same.

The voltage goes down when it is in series with another resistor that is connected to power.
For example: + Volts -> resistance 1 -> (measure here) -> resistance 2 -> ground.

So at the point "measure here" you will have less voltage, depending on the values of both resistors.

Something to add to that: Every single device (regardless what it is) it has a resistance, including the LED...
So, in your example the voltage goes down because of the resistance of the LED is in serries with your 220 ohm resistor.

8. ## Re: Fun With Electricity

Fun With Electricity Part 2

In this example we will be dimming the LED using a potentiometer.

List of things you will need:

• 9v battery
• Various lengths and colors of alligator clips
• LED light of any color you desire (This example, I will use white thats 3.3 Vf and 25 mA)
• Resistors of various Ohms (This example, I will use a 220 Ohm resistor)
• 10k Ohm Linear Taper Potentiometer
• 22 gauge Copper wire
• Wire cutters and wire strippers
• (Optional) A knob that can fit in the potentiometer with a small flat head screwdriver.

Step 1)Connect the Red alligator clip to (+) positive on the 9v battery. As you can see on the potentiometer in the image, there are 3 ends that look like little mini hoops. The first end is where we will feed the positive source. The middle is the wiper that has various voltages and resistance depending on where the knob is. And the last is ground. If we were to reverse the left and right ends where we feed our positive source, the knob will be as though its been reversed, where if you turned counter clockwise, it would be gaining voltage, and losing voltage if turned clockwise. So the ends matter. Connect the other end of the Red alligator clip and attach it to the...well assuming the potentiometer's long stick or knob end is facing you, attach it to the left end.

Step 2)Now on the right end of the potentiometer, we will need a copper wire for ground. Cut a small amount of copper wire. Length doesnt matter too much but you only need a couple inches. In my case, mine is 4 inches. Use a wire stripper to strip about a quarter of an inch off each end. Wrap one end around the right side of the potentiometer. Then attach a Black aligator clip to the right side of the potentiometer as well over the wire. On the other end of the wire, attach another Black alligator clip. We will need this later to attach it to a grounded source.

Step 3) Next I will explain the center of the potentiometer. If you were to take a digital multimeter and have it powered by a battery and having it properly grounded, the knob fully counter clockwise would show nearly 0 v, or if set at Ohms, nearly 10k Ohms resistance. If fully clockwise, it would be around 9.53 v, or nearly 0 Ohms resistance. Anywhere between would be different values depending on the knob. Now that you know, lets keep making our circuit! Attach another Red alligator clip to the middle of the potentiometer and attach the other end of the Red alligator clip to a 220 Ohm resistor.

Step 4) Attach a White alligator clip to the other end of the 220 Ohm resistor and attach the other end of the White alligator clip to the long leg of the LED light, which is (+) positive.

Step 5) Remember that Black alligator clip we were saving for later thats attached to the wire? We will attach that to the short end of the LED, which is (-) negative, and is ground!

Step 6)The other end of the other Black alligator clip thats attached directly to the right of the potentiometer will now be applied to the (-) negative end of the 9v battery.

Step 7) Now play around with the knob. The light should go from dark to light and vise versa. Have fun! And more to come!

9. ## Re: Fun With Electricity

Shaggy, I think your puns have a lot of potential but you've got to keep them current.

I can't help wondering whether Moti will wander into this thread to amp up his beef.

10. ## Re: Fun With Electricity

Originally Posted by CVMichael
It's strange... I always thought that a resistor resists the current, the voltage stays the same.

The voltage goes down when it is in series with another resistor that is connected to power.
For example: + Volts -> resistance 1 -> (measure here) -> resistance 2 -> ground.

So at the point "measure here" you will have less voltage, depending on the values of both resistors.

Something to add to that: Every single device (regardless what it is) it has a resistance, including the LED...
So, in your example the voltage goes down because of the resistance of the LED is in serries with your 220 ohm resistor.
Ehhh...The voltage of each resistor added together is the total voltage. So the total resistance is controlling the current!

11. ## Re: Fun With Electricity

Resistance that controls current??? Dam!!

13. ## Re: Fun With Electricity

Guess i was wrong. Resistors do resist current. But the funny thing is that my digital multimeter wasnt reading 9v from the led. More like around 3.4 to 3.5 v.

14. ## Re: Fun With Electricity

Yes, that is because the LED was bringing down the voltage, because of it's resistance.

I can't make a propper schematic right now (i'm at work), I used paint (for attached).

But if you try to measure the voltage through the resistor without any other resistor to bring down the voltage you will see that even if you use large resistors, the voltage is still the same as the input.

The Multimiter has it's own resistance, I think it is 1 Mega Ohm. So In theory, if you use your 9V battery, and measure the voltage through a 1 MOhm resistor, you should get 4.5V. This is assuming that your multimiter is 1 MOhm.

15. ## Re: Fun With Electricity

I just got home, and I tested what I just said in the previous post and i was right! The multimeter does have 1MOhm resistance, therefore when measuring the voltage through a 1 MOhm resistor, you get half the voltage.

So, in short, when using a multimeter to measure stuff on a live circuit, keep in mind that the multimeter is 1MOhm and in some cases it can affect the device when doing a measurement.

Now... going back to first post. I never used a formula to calculate what the resistor should be to power a LED. I use resistors that are commonly used (from schematics I see online / made by someone else). And usually I see:

For 3.3V input power, I use 220 Ohm resistor to power LED
For 5V, use 330 Ohm or 470 Ohm resistor
For 9V, use 1 KOhm, 1.2K

16. ## Re: Fun With Electricity

My 9v battery was giving me a 9.53 volts reading lol. Maybe I have a better multimeter

17. ## Re: Fun With Electricity

Originally Posted by Jacob Roman
My 9v battery was giving me a 9.53 volts reading lol. Maybe I have a better multimeter
Hmm....don't worry. Your meter is fine. A battery is just a chemical container and not a calibrated device. It will give arround 9V and will decrease in time. Also the 9V will varry dependending of the current it must deliver. In other words the battery contains a voltage device in series with an internal resistance. That resister will decrease in time and is not stable (chemical process).
If you want a stable voltage device it is better to use a power supply.

You can see a LED as a sort of clamping device. The voltage is rather constant not depending of the current it flows trough. So its certainly not a resistor. You will see however that the clamping voltage depents of the color of the LED (red, green or yellow).

The more current trough a LED the more radiation. Till a point that it blows. Most of the standard LEDs are satisfied with 10mA....20mA. The voltage over the LED is in your case ca 3V. The battery is ca 9V. So over the resistor will be 6V. (3V over the LED + 6V over the resistor = 9V battery).
You want 20mA trough the LED for example. That current flows from the battery trough the resistor, trough the LED and back to the battery.
Then the resistor must be: R=U/I=6/0.02=300 ohm. With the standard resistors use a 270 ohm or 330 ohm.

Also don't worry with the many decimals behind the point in voltages and currents. We don't build a moon lander here. In electronics we always rounding numbers if we can. For example like the resistor for the LED.

Have fun.

18. ## Re: Fun With Electricity

Originally Posted by Shaggy Hiker
... It certainly wouldn't have affected the pun in any way ...
There was a pun there?

19. ## Re: Fun With Electricity

Originally Posted by dilettante
Many people claim it came from "intensity" but I have my doubts about that.
Another popular belief is that when it came to givng Curent a quantity identifier, 'C' had already been used (Coulomb) so they used the next available letter which was 'I'. I guess that when it came to Impedence they just started at the other end of the Alphabet!!

I'm not too sure about that though; I think the Mathematicians had already used i for Imaginary Numbers. (which is why Electronics Engineers use 'j')

20. ## Re: Fun With Electricity

Originally Posted by CVMichael
Something to add to that: Every single device (regardless what it is) it has a resistance, including the LED...
So, in your example the voltage goes down because of the resistance of the LED is in serries with your 220 ohm resistor.
In fact, the LED will have two 'resistances' one forward (small) and one backward (large). The 'D' in LED means 'Diode'; which is a semi-conductor that, as the name implies, will pass current in one direction only. (up to a point)

You'll note that in these simple experiments, if you connect the battery the wrong way round, the LED will not light up at all. Also, if you put too much voltage the wrong way round you can destroy the device (it often lets the smoke out, which is not a good thing for most electronic components)

21. ## Re: Fun With Electricity

Originally Posted by Doogle
In fact, the LED will have two 'resistances' one forward (small) and one backward (large). The 'D' in LED means 'Diode'; which is a semi-conductor that, as the name implies, will pass current in one direction only. (up to a point)
I wanted to keep it simple. In fact a Diode, like a LED, is a non linear device. That means when the voltage is doubled the current will not be doubled. This implies that the resistance will varry with the current or voltage.
For simple experiments we can say that the voltage over such devices is constant.
http://en.wikipedia.org/wiki/Light-emitting_diode

22. ## Re: Fun With Electricity

Originally Posted by Doogle
Another popular belief is that when it came to givng Curent a quantity identifier, 'C' had already been used (Coulomb) so they used the next available letter which was 'I'.
'I' comes after 'C'? I know the rule "I before E except after C....", but in this case, I find it hard to believe that 'I' was the next available letter.

D - ?
E - electron, or energy, but that use of E seems later.
G - gravity?
H - ?

23. ## Re: Fun With Electricity

Is is against the unwritten chit-chat rules to mention Wikipedia?

Well, I'll take the chance. Apparently "I" was coined by Andr&#233;-Marie Amp&#232;re who, despite or perhaps because of his gender-confused forename, was a Frenchman. And it stood for intensit&#233; de courant. One British journal hung on using C instead of I until 1896, when it finally gave way to the pressure of French logicality.

BB

24. ## Re: Fun With Electricity

E might have been 'e' (2.718 etc)

H is Henrys (measurement of Inductance)

25. ## Re: Fun With Electricity

Fun With Electricity Part 3

This is one of my favorite experiments. In this experiment, you will be playing around with an actual NES controller. And can open doors for some modding such as this:

Or even this:

Or this:

Trust me. Its easier than you think. And I'll show you how. Before we start. I wanna talk to you about how an NES controller works. Remember the 7 prongs at the end?

As you can see from the diagram. That's what they do. However, on an NES controller, only 5 are used because its not a Zapper, Power Glove, or any other special device. So disregard D3 and D4 which are reserved for special controllers. Now when you take apart your NES controller, you'll notice 5 different colored wires:

Here is what they do from top to bottom:

White: 5V DC Input
Orange: Shift Register Latch, or just Latch for short.
Red: Shift Register Clock, or just clock for short.
Brown: GND, also known as Ground. Duh.
Yellow: Data Out

You will also notice a chip on the circuit. This is known as a 4021 Shift Register. Although not that important in the experiment I am about to show you. Its simpler than you think to know what they do and can open doors for even more modding . Here is what each of the pins do:

And if you follow your little eyeball in the back of the circuit boards little paths, you'll notice that they do in fact connect with those buttons.

Currently 5V DC is running through the circuit board with the NES on. (5V - 1.7) / 0.02 A = 165, which means the closest resistor you'll need is a 150 Ohm resistor. If you press the Start button, it will cause a short, showing start has been pressed. Same holds true with B, A, Select, Up, Down, Left, and Right. Knowing this, you can make LED lights light up when you press a button, which is cool if successfully pulled off, but we will do something different in this experiment. In this we will just light up a red LED.

In this experiment, you will need the following:

• NES
• NES Controller
• NES Power Supply and RCA cable
• Red and Black spare copper wires
• Alligator clips
• A 150 Ohm Resistor
• Red LED 1.7 Vf 20 mA

Step 1) Be sure your power is off before you begin. Take apart your NES controller by removing the 6 screws on the back. You'll only need the circuit board and cable for this experiment.

Step 2) Plug in your NES controller but keep the power off. Start with the red wire already pre stripped on both ends. Connect a Red alligator clip to one of the ends. Connect the other end of the alligator clip to a 150 Ohm resistor.

Step 3) Connect a White alligator clip to the other end of the resistor and on the other end of the White alligator clip, connect it to the long end of the red LED light, which is (+) positive.

Step 4) Connect a Black alligator clip to the short end of the red LED light, which is (-) negative. And on the other end of the Black alligator clip, connect a pre stripped Black wire.

Step 5) Next, remember the circuit board shown above?

On the right side of the image you'll see 5 large solder points. The top one as I already explained is 5V DC power. Place the free end of the Red wire on top of that and carefully clip it down using an alligator clip on the circuit board to hold it down. Don't try clipping the solder point itself, as it won't do it and just slip off.

Use the free Black end of the wire to place it on top of the 4th large solder on the right side. This is GND, or Ground. carefully use the other alligator clip and clip the wire down on the circuit board to hold it down. Since its kinda far from the alligator teeth, you'll just simply clip the wire itself down, which forces it down a notch. As long as the copper end is on top of the 4th solder point.

Step 6) Turn on your NES and watch it light up magically before your eyes. You can even mix experiment Part Two in this and add a dimmer switch. And with some slick soldering skills and a drill, you can even solder the same circuit to eliminate the need for alligator clips, and build your own LED lit NES controller. Happy modding /wave

26. ## Re: Fun With Electricity

Originally Posted by Shaggy Hiker
Resistance that controls current??? Dam!!

27. ## Re: Fun With Electricity

I never understood the 'triangle': I always have remembered V=IR (as well as P=IV). Basic math will give you the rest.

As far as fun with electricity goes, wiring a relay coil in series with the normally closed contact and supplying power, typically a 9V relay. Touch the relay coil pins...

28. ## Re: Fun With Electricity

I wonder what they used to cut out the NES logo the controllers?

29. ## Re: Fun With Electricity

Originally Posted by Jacob Roman
I wonder what they used to cut out the NES logo the controllers?
I mostly just wonder what word was cut out of that statement to render it the way it is?

30. ## Re: Fun With Electricity

Originally Posted by Shaggy Hiker
I mostly just wonder what word was cut out of that statement to render it the way it is?
"On". Stupid phone deleted my words

31. ## Re: Fun With Electricity

Fun With Electricity Part 4: Using an AC power cable Plug instead of a traditional Power Supply

Get ready to develop some balls cause **** is about to get real. In this experiment we will use a standard AC power cable with one end being Squared and Round while the other end is a plug. This same cable is used in many electronic devices such as an old playstation, ps2, xbox, sega saturn, small portable stereo, etc., and looks like this:

In this experiment you'll need:

• AC power cable
• An AC power cable jack to be removed from an old device
• An NES
• A small 12V DC power supply (keyword small)
• Soldering Iron
• Solder
• Desoldering wick
• Wire Cutters
• Wire Strippers
• A standard screw driver

Step 1: Open up the NES using a phillips head screw driver. Removing the top from the 6 screws, and the RF shield with 7 screws. Leave just the circuit. cartridge connector, and cartridge loading mechanism, as well as the plastic base. Be sure the NES is NOT plugged in as you do this.

Step 2: Take your 12V DC power supply and pop it open using a standard flat head screw driver. Be patient. This will be the hardest part of the project as it is a royal pain to do this. They were not made to be open. You can do this with any 12V DC power supply with a reasonable amount of amps, but if you plan on putting it into your NES, you will need a small 12V DC power supply.

Step 3: Now that you successfully opened the power supply you will notice 2 wires soldered onto the plug. You can either desolder em off or you can simply cut em with wire cutters and use wire strippers to remove some of the outer area of the wire so you have something to work with. Be weary which wire is which. This is important! Assuming top view of when it was originally connected to the plug, the left wire is negative (-) and is also ground. This is usually indicated on your plug as a color strip that runs all across your wire. The right wire is positive (+). Save the base as you will need that to prevent shorts.

Step 4: Open up a device you no longer want to use for the ac power cable jack. In this case I removed it from a non working Sega Saturn, and is nice cause it has 2 screw holes. Desolder this from the board and remove it.

Step 5 Next you will need to know which end is positive and which end is negative off the metal ends of this ac power cable jack. The square side is negative (-) and the round side is positive (+). Go ahead and solder the negative end of the power supply wire to negative on the AC power cable jack. Then solder the positive end to positive.

Step 6 Plug in the AC power cable to the power cable jack, and plug in the power supply end to the NES. Pop in your favorite game and it should work. If it works. Continue to step 7.

Ste[ 7 Inside the heatsink of the NES is a 7805 voltage regulator. From the top view there are 3 prongs. The left prong is where you will feed 12v DC in. The middle prong is ground. And the right prong is where it'll output exactly 5V DC. Remove this 7805 voltage regulator using a phillips head screwdriver. Snip the power supply wire using wire cutters, the end that plugs into the nes, leaving only a foot or so of cable. Use wire strippers to strip it. On the NES theres another circuit board located where the Power and Reset buttons are. 5 wires are coming from this. Here is a good diagram on what they do:

Brown and Red are for the Power Button, where Red is powered when the power is on while Brown is always powered.
Orange and Yellow are for the Reset Button, where if pressed, itll link Orange and Yellow and cause it to short, causing the system to reset.
White is the LED power.

Where the large blue connector attaches are 5 large solder points. Solder on the positive end of the power supply wire onto where the Red wire attaches to onto that solder point over the blue connector so we can still control it using the power button. Next Solder the negative end of the power supply to the ground of the 7805 voltage regulator. Next solder a spare wire onto where 5V DC is outputted on one end of the 7805, and have the other end go where... you see 5 other large solder points over the RF modulator all in one horizontal row? Solder the other end of that wire to the middle one. Now attach the AC power cable jack anywhere you want in the back of the NES (you may need a drill and cutting tools for this one), and find a safe place to put the small 12V DC power supply in the NES. Have it held down with epoxy or hot glue and only this time you are not using the base of the power supply. Just the naked circuit of it. Be sure its not touching the NES circuit in any way besides the wiring portion.

Step 8: Power it up and test if it works. Congratulations. You no longer need a clunky power supply.

32. ## Re: Fun With Electricity

learned all of this in technical school 4 years ago (yes when i was 14 years old)

i love electronics for some reason

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