Understanding Electricity….Really.

by Guest Blogger on January 27, 2014 · 30 comments

man with a hammerUnderstanding Electricity….Really.     By  Dave Bailie www.survivalpuck.com

When it comes to survival, a person with a solid working knowledge of electricity can be a very valuable asset. You might be a bit rusty, here is a little refresher.

Even though electricity plays a huge role in so much of our lives, the average person has little understanding of it. You flip the switch the light comes on, what’s to understand?  Other than seeing a spark or a lightning bolt, electricity is invisible, we can’t handle it we can’t hold it in a bottle. We are left with only describing its effects which does make it hard to wrap your head around.

Electricity is just the movement of electrons no more no less. All materials are made of molecules and all molecules are made of atoms. All atoms have electrons orbiting around the center of the atom. When an electron from one atom makes the jump to another atom this is electricity, just electrons moving from one atom to another.

Electricity is pretty easy to understand if we relate it to something we are all familiar with and that’s water. I’m going to use a pump and a hose as an illustration.

Let’s think about a water pump. Pumps have two common ratings, the pressure they can supply the water at in pounds per square inch (PSI) and how many gallons of water they can pump in one minute or gallons per minute (GPM).

Then we’ve got the hose, there are two things to consider, the hose diameter and how long it is.

So let’s say you have a pump that puts out 12 psi of pressure and can pump up to 30 gallons per minute of volume. This pump is hooked up to a 100 foot length of half inch diameter hose. When the pump is running we get 8 gallons per minute of water coming out of the hose. Now how can we change the amount of water coming out of the hose?

One way is to increase the pressure coming out of the pump. If we double the pressure to 24 psi we will get 20 gallons per minute. We have doubled the force pushing the water down the hose so we get twice as much thru that hose. If we cut the pressure in half to 6 psi we will get half the volume or 5 GPM.

Another way is to change the flow is to change the hose diameter, if we go to say a one inch diameter hose this larger hose will have less resistance to the water and we might go from 8 gallons per minute to 12 gallons per minute. If we keep going up in hose size we will hit a point where the pump is putting out its full 30 GPM capacity. At this point we can’t get any more out of the pump and making the hose bigger doesn’t help. Now if we decrease the hose size down to one quarter inch this might knock the flow down to 4 GPM because it’s harder for the pump to push the water thru this small hose.

The last way to change the flow is to change the length of the hose, a shorter hose has less resistance and will flow more GPM then a longer hose. Stick 500 or 600 feet of hose on our pump and the flow might be down to a trickle. In this case almost the pumps pressure got used up trying to push water down this long hose.

All of this is pretty straight forward and easy to understand right? If this example makes sense to you then you already understand how the three basic units of electricity work together. These three basic units are Volts, Amps and Ohms.  As you might have guessed electricity behaves much the same as water.  Volts are just how we measure that electrical pressure, except this pressure pushes electrons instead of water. Like the PSI output of the pump right?  12 psi= 12 volts got it?

Ohms is how you count resistance to flow, a small diameter hose has higher resistance than a larger diameter hose. Small hose =high ohms and a large hose= Low ohms, less ohms= less resistance= more flow.

Amps are just the volume of electrons that are passing over a certain amount of time just like gallons per minute. One amp is an actual number of electrons flowing past one point on a wire in one second. If I recall the number of electrons in one amp was a number with something like 67 zeroes behind it.  I just know it’s a big big number.

Here are some examples to tie these together. Our bodies have pretty high electrical resistance that’s why they don’t make electric wire out of meat. So we can grab hold of both the positive and negative posts on a 12 volt battery and not be shocked. 12 volts is pretty low electrical pressure and our bodies have a lot of resistance to electrical flow or ohms, just like a very small diameter hose. So even though a tiny bit of electricity measured in amps is flowing up one arm and down the other it’s not enough for us to feel it or do any damage. Now if we tried this with a 120 volt battery the electrical pressure would be ten times higher.  This higher voltage is pushing those electrons up one arm and down the other with ten times more force so there is ten times more flow or amps. You will be shocked for sure.  Generally its somewhere around 48 volts that starts to present a shock hazard. You could call our bodies semi-conductors we don’t flow electrons too well.

Metals like to flow electrons so we call them conductors. Some metals have lower resistance than others which makes them better to use as wire. Gold is best, followed by silver and then copper. Aluminum is good steel is fair.

If you take a piece of wire and lay it across the + and – on a 12 volt auto battery (dead short) it will quickly turn white hot and melt.  Wire is a good conductor but not a perfect conductor. The imperfect part that creates resistance turns some of the energy into heat within the wire. It takes a lot of amps flowing to cause this kind of heat. As long as the battery can continue to supply enough amps the wire is going to melt. If you tried the same experiment with a small 12 volt battery say AA sized, you might just get a little spark and I’d be surprised if the wire got hot at all. The little battery will do its best to feed amps through the wire. But it’s too small for the job and cant pump out electrons fast enough to keep the voltage up and it drops rapidly along with the amps. Remember this: it is high amps that cause things to smoke. High amps can be caused by high voltage but more often it’s due to low resistance, some manner of short giving the electricity an easy flowing path.

The big battery can supply much more power than the small battery. Notice this is the first time I’ve used the word power. Power is the bottom line; it takes power makes things happen. Sometimes you just need a little for LED headlamp and some time you need a lot to start an engine. Engine power is measured in horse power. To figure horse power (HP) you need to know two things, how fast its spinning (RPM) and with how much torque or twisting force the engine can maintain while keeping up the spin speed. Electrical power is measured in Watts. Just like horse power you need two things to figure out Watts, they are Volts and Amps.  Volts x Amps= Watts simple as that. 746 watts equals 1 horse power.

Consider the 1200 Watt blow dryer you may have in your bathroom. Hard to believe but that blow dryer takes nearly 2 horse power to operate. That’s close to the horse power found on some lawn mowers. It’s kind of incredible that all that power can travel thru the power cord. Let’s do the math; I know the voltage at the plug is 120 Volts so if I divide 1200 watts by 120 volts I find out that we are flowing 10 amps, well within the safe range for the size of the power cord. Now I decide to build a blow dryer to run on 12 volts but still put out 1200 watts of power. If a do the math knowing I only have 12 volts to work with it tells me I need a whopping 100 amps. At this flow of amps your standard size RV battery might run this blow dryer maybe 20 minutes until it was dead. This would require wires about as big around as a pencil to carry that many amps. Not too handy in the bathroom, luckily I checked the math before I started. The original cord would have smoked at 100 amps. As you can see it’s much more practical to get higher power using high voltage rather than higher amps or as more commonly called current.

Notice this is the first time I’ve mentioned current and I did this for a reason. You may have learned that current will travel from positive to negative thru a wire. This is called conventional theory and it’s wrong. Electrons flow from negative to positive. Nothing flows from positive to negative. How you ask can this be. I asked an instructor this question years ago. He gave me some BS explanation that the electrons were flowing one way and the gaps between the electrons were going the other way and that was current. It didn’t seem right to me so I tracked down the answer.

Its Ben Franklin’s fault, he found that rubbing wool and wax would produce a little electricity. He surmised that the electrons were traveling from the wax to the wool. He decided the wax was positively charged with extra electrons and the wool had a shortage of electrons and called it negative. It wasn’t until years later that experiments were able to prove he got it wrong and that electrons really travel from what he called negative to what he called positive. By then it was too late everyone had been using Bens rules and we still use them today. For all intents and purposes it doesn’t really matter. Amps and current are terms used interchangeably.

Hope this helps, if this foray into electricity flies I’ll do a few more and just add to what we learned today. It’s what’s between your ears that will keep you alive.

Dave Bailie is the owner of www.survivalpuck.com - compact survival kits…

30 comments… read them below or add one

mom of three January 27, 2014 at 10:43 am

Yep, hubby is an electrical contractor, great information.

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JP in MT January 27, 2014 at 11:13 am

The government spend a year teaching me about electricity and electronic circuits in the 70′s. The basics are just that, pretty basic as explained above. (Of course it took the government a lot more time and resources to teach the same thing.) I still have no problem with DC circuits, even though some of the 26 amp circuits I used to work on would fry you quick, I still get the “willy’s” working around hoursehold current. Go figure.

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Nightshiftsucks January 27, 2014 at 4:50 pm

I think it’s about 26miliamps will kill you.I work on diffusion furnaces sometimes,when they are firing at 100% it’s 180 amps,got to be careful

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Michele January 27, 2014 at 12:05 pm

I’m pretty lucky too, DH is an electrician.

I had to study all this to get my HAM license – many years ago, but lack of use leads to forgetting – and I’ve forgotten all this.

Thank you for the refresher – although for anything we really need to get done, I’ll let DH do it.

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bctruck January 27, 2014 at 12:37 pm

My parents were convinced i would grow up to be an electrician since i had such an interest in sticking things in the outlets as a child. i actually dveloped an unhealthy fear of messing with electricity, eben as a jerk of all trdades that i am,i still call the experts whe dealing with electricity. This does explain things more clearly especially for someone who fears getting zapped again.

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mom of three January 27, 2014 at 1:54 pm

Even the best of them get shocked, hubby’s nick name is Sparky. The one project he had to do on a weekend, and no one could be around him. He was working on a live panel only the office manager, who is our friend was allowed to be there in case something happen to him.

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Bubster January 31, 2014 at 5:35 am

Any electrician who’s never been shocked has never worked on anything live, or is just a liar.

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kts532 January 28, 2014 at 1:18 am

I Thought all kids that stuck things in electrical sockets grew up to be Firefighters.

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Rob Crawford January 28, 2014 at 9:04 pm

Some of us do end up as electrical engineers.

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Bctruck January 27, 2014 at 4:05 pm

Just came in from the mail box and I’ve received my survival puck #4 (fire). Just wanted to thank Dave, the owner of survival puck,for being an advertiser on the webs best survival blog and especially for being a sponsor of the writing contest. I opened it up and it includes everything one would need to start a fire under the worst of circumstances. It’s going right in my new get home bag from luckily gunner,with a few dehydrated meals in it from LPC survival. Thanks again Dave!!

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Cain January 27, 2014 at 4:50 pm

Interesting starter into the topic of electricity, but I would have liked to see more practical knowledge and application in the realm of prepping.

Examples I’d love to see:
Solar panel and wind power systems, setups, and explanations.
Difference of direct current versus alternating current (for those unfamiliar with the topic altogether).
Wiring in a household setting related to breakers and wire gauge (based off the fire hose example).
Power converters from a car battery to 120v AC – how it works in case and what to look for in case you need to repair a power converter.
Tools every person should have.

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will e styles January 27, 2014 at 7:47 pm

I so agree,with Cain. I would love to see more like the ones mentioned as well as how to connect a gen back to the house safely.

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D Bailie January 27, 2014 at 11:39 pm

Thanks Cain
I will write more on the subjects you mention.
Just thought it was a good idea to start at the start.
This is a tricky subject that can kill you.
Thanks again
Dave

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Cain January 28, 2014 at 12:15 am

Another item or two to add to that list would be grounding and insulating electrical lines and circuits. Crash course into voltmeters always helpful. Emergency generators could be something to look at.

May also be a lead into devices like Faraday cages.

You could also go into why its bad to overload wire. Effects to wire insulation with loads over 80% of a wire gauge’s rating for a prolonged period of time.

I’d considering write ups on the subject, but about the only thing (outside power related issues regarding computers) I am really good at is electrocuting myself.

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rjarena January 28, 2014 at 11:19 am

I used to run big box retail stores, and I used to hate the “do it your-selfer” that would not listen to professional advice. I would tell them “this is not like working in your yard, this serious stuff, it can burn your house down or kill you dead”.

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Chuck Findlay January 27, 2014 at 6:06 pm

I’ve worked with electricity for over 40 years (still do) I honestly think most (95%) people will never understand it and are not capable of understanding. I have seen countless ways people mess up, do wrong and in a very dangerous way do things with wire and electronic items.

This is one area where you should go find a professional to do a job. Yea you may get away with cutting corners (and never even understanding you did cut corners) and get away with it. But that doesn’t make it safe, and at some point when just the right situation comes about people can get hurt / die and or your house can catch fire.

We live with electricity in our lives every day and we come to think nothing about it. and we think it’s easy to understand. But it is a vastly more dangerous then most people think and like fire it’s great when it’s working as we want it to, but it also can get loose if not respected.

I know electricians charge a lot and what they do seems simple. But it’s not that simple and things can and do go wrong.

Electricity is not like building a chicken coop or pouring concrete for a walkway. electricity must be respected or it will bite you hard.

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Col. D January 27, 2014 at 9:18 pm

Chuck, I couldn’t agree more, trying to safely teach electrical theory in a few paragraphs isn’t likely but Dave does provide some excellent analogies. Like yourself, I’ve been working around electronics and electricity for over 40 years and among my many talents I am an engineer and electrician.

A novice should hire a professional to protect themselves, their families, and equipment when / where possible. Someone can get killed or hurt badly working around electricity without proper education, training or real experience. There is a saying in the industry; ‘one blunder six feet under’. I have seen instances where people have been electrocuted by being careless while working on and around live circuits. These were experienced tradesman or helpers who should have known better but got careless or cut a corner. Unfortunately it cost them their lives.

Someone asked about wire gauging, for wire sizing type information (gauge) I use the National Electrical Code handbook tables from the latest edition which is currently NEC-2014. This is also called NFPA-70 NEC. It’s published by the National Fire Protection Association (NFPA). This changes every 3 years due to various technology changes and other factors. The newest 2014 code edition is now available on NFPA’s website at;
http://www.nfpa.org/codes-and-standards/document-information-pages?mode=code&code=70
A secondary source of information can be found on the International Association of Electrical Inspectors (IAEI) website at;
http://www.iaei.org/store/ListProducts.aspx?catid=225181

The NEC-2014 book would be of little use to people without some rudimentary education on electricity, however for the experienced electrician / contractor it allows them to look up specific information for various installations of electrical services or equipment. The purpose of the NEC is to provide minimum standards or guidelines in regard to safe installations in commercial / residential electrical applications.

I would encourage anyone interested to consider taking a basic electricity course from a local technical college or trade school. It will provide a student some basic understanding and knowledge about electricity. Many schools offer day or evening classes for those who are interested. Who knows, it may open a whole new world for you.

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Wilson Lee January 29, 2014 at 9:50 pm

I couldn’t agree more about taking a basic electrical course from a community or jr college. Be sure it’s in their technical/trades area. It may be 1 or 2 semesters long. The one I took a few years ago was 2 short terms in one regular semester where we covered both AC & DC fundamentals.

Keep in mind some institutions may use these courses as an ‘eliminator’ to make sure folks are serious…

And then you can decode: PIE & EIR :)

Wilson

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Texanadian January 27, 2014 at 10:06 pm

I have rewired old houses, built building and ran the wiring and done all kinds of electrical fixes. Every major project I got an electrician to check my work and make the final connections. An error anywhere can cost you and your family your life. I always watch them and can probably do it myself but I am not willing to take that chance with my family and my investment. Houses burning down really sucks. Never happened to me but I know other do-it-yourselfers who paid the price.

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Western_Reservist January 27, 2014 at 9:34 pm

I got Lesson #1 in electricity in 1950 when I was a wee tyke and Pa was demolishing our goat barn with a circular saw. He unplugged the saw, but left the “hot” extension cord dangling where I could explore it.

I poked a small metal nail into one of the female slots of the hot cord and held on to it, or rather, I should say, the 120v “held” onto me!

Lucky Pa was a few steps away and saved my sorry self.

Sixty five years later, I still give GREAT RESPECT to Mr. Electricity….

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Survivor January 28, 2014 at 5:16 am

My son was still in diapers and wanted desparately to stick something in those little holes in the wall. The ex followed him around like a mama hen telling him, “no, no..mama ‘pank”. One day she left me in charge and I let him stick it in. Kinda funny, I didn’t have to tell him once and got better results.

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kts532 January 28, 2014 at 1:32 am

As a Firefighter/Paramedic I have seen the result of people that do not understand Electricity to many times. Please hire someone that KNOWS what they are doing. Your family will thank you. You or your loved ones will die if not done right. Bodies don’t do well with electricity. Most houses burn because of electricity.

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OhioPrepper January 28, 2014 at 12:38 pm

Dave,
This is an interesting article with a good analogy using water pressure and flow rate.
Actually current is the flow of electrons, which is measured in Amperes. As Dave stated, amperes are measured based on the number of electrons passing a point in the circuit in 1 second, with one ampere being 1 coulomb (6.241 x 10^18 or 6241 followed by 15 zeros) electrons..
The amount of power required to harm or kill a human depends on where it is introduced. If the power stays on the skin, the relatively high resistance will keep the power low; however, if you break the skin, the blood, which is basically a low resistance salt water conductor has much lower resistance, and will allow more current (and thus power) to flow. Additionally, if the power travels across the region of the heart, you can shock the heart’s electrical system into failure. The rule I was taught and always use when working with high voltage is to keep one hand in your pocket, so no path can form across the chest.
One common misconception on conductivity is that gold is the best conductor, and although it’s a good conductor, it falls below Silver, Copper, and Annealed Copper. Gold is often used as a conductor or a coating on a conductor because it does not react with most atmospheric gasses or contaminants, and there for remains stable over time.

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D Bailie January 28, 2014 at 2:57 pm

I stand corrected.
That’s what you get from going by memory.
I did check a couple sources and copper is a better conductor gold too.

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Rob Crawford January 28, 2014 at 9:08 pm

Something to remember — the statement that “electricity takes the easiest path” is WRONG. Electricity takes EVERY path. Most of it does take the “easiest” path — but not all of it.

So always be sure the power is off, regardless of what appears to be shorting out the current.

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Chuck Findlay January 28, 2014 at 10:29 pm

You definitely need to check the power before you work on it. But it’s a frequent occurrence in the homes I work in that the hot and neutral are reversed and while the power seems to be off you can still get bit. Like I said above people wire things wrong every day and it still can work but not right. Almost every home I work in has at least a few plugs wired wrong or no ground.

You can buy a $15.00 and under tester from any home depot type of store that will tell you if a plug is wired correct.

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Salem January 29, 2014 at 8:46 pm

You actually need 2 inexpensive testers to be safe. Mike Sokol at http://www.noshockzone.org/ has been evangelical about protecting people from being killed by RPBGs. Not by rare military ordnance, but by Reverse Polarity Bootleg Grounds.

To explain – the standard three light tester shows the voltage relationship between pins in an outlet: green light from black to white, green light from black to ground, and red light from white to ground. To the average person, and perhaps many electricians, two green and no red is good. Red indicates that the hot and neutral are reversed, but only if the ground is a real “non-bootleg” ground.

So here’s the problem. Maybe someone is adding an outlet to old wiring with two lines and no ground wire. I understand the correct thing to do would be to install a GFCI (Ground-Fault Circuit Interrupter) outlet there and mark the outlet as no ground. But what many would do, especially if the carpenter is doing the wiring and the building inspector is coming, would be to add a jumper from the white wire terminal to the ground terminal. The neutral and ground are tied together at the service disconnecting point anyway, right? This is a “bootleg ground.”

So we or the inspector plug in the tester, see two green and no red, and sign off on the safety, right? Well, there might be the chance that the polarity was reversed. Say there was some old knob-and-tube wire in the circuit, and the white threads had faded so both lines look black. If the wrong line was picked at the neutral, the outlet polarity would be backwards. With a real ground at the outlet, the red light would warn us. With a reverse-polarity bootleg ground, the tester has been fooled dangerously by the white and the ground both actually being hot.

The appliances plugged in don’t care which side is hot, but the metal case of anything plugged in with a 3-prong plug is immediately live. Touch the case of your PC and the radiator at the same time, and you are 6 feet under.

So the other tester you need is the kind you only stick into one prong at a time, and do not complete the circuit. Your body is kind of an “antenna” that senses the ground and lets a neon bulb (in my day) or other indicator lights up when touching a hot wire. After seeing two green and no red, stick the tip of the second tester into each opening. It should light in the short slot, identifying the hot. It should NOT light in the ground hole, nor in the longer or T-shaped slot. If it lights in the other openings, find the problem in the work, or engage a professional before someone gets killed.

Disclaimer: I am not an electrician, but I have been known to tell electricians what they should do.

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Fluids Guy January 30, 2014 at 10:00 am

Unlike in a DC circuit where current varies proportionately with voltage, fluid flow varies proportionately to the “square root” of pressure. Simply stated, doubling pressure will increase flow, but not double it. Fluids Guy.

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Dog Log February 1, 2014 at 1:46 am

Some thing else to be aware of is, it was not uncommon to “share” a neutral or white wire between two phases, or two circuits, two separate breakers. If you break the joint between neutral wires that has a load on it, you will get the load, just like the “hot” wire, but maybe worse.
Residential electrical panels are what you call “single phase”, but actually have two phases. For instance, A phase,and B phase. While commercial panels will most likely be three phase. A phase, B phase, and C phase. When you look at your breaker panel, you see they are numbered, odd down the left side, even down the right side. A residential panel will be numbers 1 & 2 A phase, 3 & 4 B phase, 5 & 6 A phase, 7 & 8 B phase, and so on down the panel. A commercial panel will be, 1 & 2 A phase, 3 & 4 B phase, 5 & 6 C phase, 7 & 8 A phase, and so on down the panel.
Also your wire color should tell what phase your circuit is, but not always in a residential panel, just because of the type of wire or cable that is used to commonly wire a home. Commercial should always be color coded. Your color code also tells you what voltage level it is. For example, 120/208 volts will be Black A phase, Red B phase, Blue C phase, with a White neutral, and a Bare or Green ground, depending on wire type used. In a commercial panel. 277/480 volts will be Brown A phase, Orange B phase, Yellow C phase, with a Gray neutral, and a Green ground. And these are AC or alternating current.
And with that being said, when you step into an Industrial environment, it can be a whole new ball game, with even more wire colors that are not necessarily standardized.
And then there is DC or direct current, where for instance the White wire is the “hot ” wire, and the Black wire may be like the neutral or ground wire.
Some things are best left to a pro, and even then not every electrician knows it all. There are many variations, or specialties of the electrical fields.

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Dog Log February 1, 2014 at 1:57 am

I would recommend that you find a book that deals with the specific area that you are interested in.

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