Notes

Electricity

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https://m.youtube.com/watch?v=J4oO7PT_nzQ

https://m.youtube.com/watch?v=-EB7NVA7rI4

https://m.youtube.com/watch?v=VnPRX5zQWLw

https://m.youtube.com/watch?v=THSNzVax8og

https://m.youtube.com/watch?v=zLW_7TPf310

https://yewtu.be/watch?v=rtnmCf2QFTc

https://m.youtube.com/watch?v=0nS-HQ1PKMQ

https://m.youtube.com/watch?v=4VNdr_v9Ct8

https://m.youtube.com/watch?v=R_VlWQa0lpc

https://m.youtube.com/watch?v=X4EUwTwZ110

https://m.youtube.com/watch?v=hoYIzmItja4

https://m.youtube.com/watch?v=LyekAmnJnOA

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resistor - less current on the other side of resistor than on starting side of resistor, resists electrical flow (current)

resistance - measured in ohms, higher resistance - less current

transistor = resistor that you can control with input signal

Capacitor - ac enters, dc exists.
t has the ability of charge and discharge, preventing DC current from passing through, allowing AC current to pass through.

Capacitance is the ability of a component to store electric charge and can be measured with units called Farads. A capacitor with high capacitance (say 1.0F) can store more energy than one with low capacitance (say 1.0mF).

We measure voltage in the units of Volts. This is the maximum voltage the capacitor can handle

We measure the capacitance of the capacitor in the unit of Farads
Circuit boards typically use microfarads (uF)

We measure voltage in the units of Volts. This is the maximum voltage the capacitor can handle

Store high voltage values for a long time. Even when disconnected from a circuit

DC capacitors are used in electronics, while the AC type are motor start capacitors.

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In an electrical circuit, a neutral wire delivers the remaining power that was left after your smart switch or any kind of appliance draws current, back to the transformer outside your house. It is a path created to facilitate that residual current goes easily back to the energy company.

* Hot wire: Commonly coded with red color at least in the U.S. Basically is the first path that the electricity takes from the transformer outside your house until any kind of electrical device connected to the circuit.
* Neutral wire: Once any type of your household appliances draws current from the electricity company A.K.A the transformer outside, there is a residual current that needs to go back! And this wire is guilty of it.
* Ground wire: In case something terrible happen with your switch, fridge, or any device, the Ground wire will redirect that current directly to the source, avoiding an accident. If you’re lucky enough you won’t use this cable never in your life.

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A neutral wire has the ability to return electricity to the panel breaker up to its power source, which is the transformer.
On the other side, the purpose of the ground wire is to provide an emergency path for electricity to flow into the earth. In other words, it is to protect anyone from electrocution at times of ground fault.

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The ground circuit is connected to earth, and neutral circuit is usually connected to ground. As the neutral point of an electrical supply system is often connected to earth ground, ground and neutral are closely related.

Ground wires run parallel to other wires in order to safely discharge excess electricity into the ground.
If something were to short circuit, the ground wire would be the alternate pathway to stop the flow of electricity.
What is the Purpose of a Ground Wire? 
The purpose of a ground wire is to safely direct excess electricity from your home into the ground. Electricity works to eliminate the negative currents from an electrical system in order to return to equilibrium. Under typical circumstances, neutral wires lead the way for currents returning to the breaker panel to restore equilibrium.

However, if an issue arises in the normal process of electrical flow, energy can be passed to other parts of your home, such as pipes or wood framing, increasing the likelihood of a house fire or shock. This is an example of a short circuit.
Ground wiring is there to prevent this and to allow currents to escape through it, rather than through other parts of your home that can cause damage or harm to your home and family. 

An electrical current needs to find a pathway to the ground in order to neutralize. Electrical ground wires provide a safe pathway, acting as an absorber for the electrical shock.
Large electrical surges can occur when there are lightning strikes or system malfunctions, but it’s not uncommon for a home to have smaller power surges throughout the day. It is common for this to occur when you use many devices in your home at once, especially larger appliances. 
If your home has ground wires, that electric energy escapes safely. If it does not have proper grounding wires, electricity can travel to dangerous places in your home. This can lead to damage to your appliances. Electricity can also escape through other pathways such as your home’s structure, potentially causing electrical fires. 
In the worst-case scenario, that excess electrical energy can travel through you. When you get an electric shock, the outcome can be devastating. Electric shock can cause severe damage to your body and even death, depending on the amount of electricity. 

xcess electrical charges are common in any home. They’re the reason we safeguard our electronics with surge protectors, which means they include surges from things like lightning strikes and transformer malfunctions. But they also tend to occur several times per day, whenever large appliances start up; if you’ve ever noticed your lights briefly flickering when your air conditioner kicks on, that’s due to a minor surge of excess electricity.
In a properly grounded electrical system, that excess electricity goes directly into the ground. But if your home has electrical outlets that aren’t grounded, the surge could go in a number of dangerous ways.
The most dangerous way is if the electricity finds a path to the ground through a human body. This can happen if you touch an ungrounded plug or outlet at the wrong moment -- the electricity can travel between the part of your body touching the outlet and your feet on the floor, causing burns, nerve damage and even death, if the surge is powerful enough.
If the surge of electricity finds a path through the structural elements in your home, it can spark a fire. And there’s always the chance that the electricity will flow directly into appliances and electronics that are plugged into ungrounded outlets, which can damage them.

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In most cases the driver would be safe, but the vehicle would be compromised. The lightning would strike the chassis, and current would flow along the outside of the vehicle and into the ground, protecting the occupant inside similar to a Faraday Cage.
However, the surge in current would likely destroy the car’s electronics, potentially deploying the airbag, blowing out the tires, or in the worst possible scenario, set the battery or other parts of the car on fire.
The driver could potentially be shocked if they are in contact with any metal parts of the interior, such as door handles, or if they are driving a vehicle that does not have a metal top, such as a convertible, which case the lightning strike would burn right through the top and into the interior of the car as if the top wasn’t there, which would be bad news for anyone inside.

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"Ground" is just another word used to refer to current return common circuit.
There is a complete circuit because everything electrical inside the car such as the starter the electric windows etc connect to the ground in order to return the current to the minus terminal of the battery. The car body and chassis is utilised for the return and thus the chassis and body are considered to be the ground and pretty much an extension of the minus of the battery.
Car makers could have a wire from each electrical device in a car leading to the minus of a car battery. This would very very quickly become a huge mess as you would need many many wires for each device.

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Electric shock is the physiological reaction or injury caused by electric current passing through the (human) body. Typically, the expression is used to describe an injurious exposure to electricity. It occurs upon contact of a (human) body part with any source of electricity that causes a sufficient current through the skin, muscles, or hair.
Very small currents can be imperceptible. Larger current passing through the body may make it impossible for a shock victim to let go of an energized object. Still larger currents can cause fibrillation of the heart and damage to tissues. Death caused by an electric shock is called electrocution.

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“Can you get electrocuted if you are not grounded?”
You are much less likely to be electrocuted if you aren’t grounded. The reason for that is to be electrocuted you must be touching two points at different electrical potential. As most electrical supplies are referenced to earth/ground potential, if you, yourself, are grounded then all you have to do is tough a “live” wire. However, if you are not grounded and have what’s called a “floating” potential, then just touching one wire will not cause you to be electrocuted. It is why birds can perch, unharmed, on live wires. For you to be electrocuted when you have “floating” potential, then you would have to touch two different wires at different potential.
However, if you are handling electrical circuits, it’s quite likely you will have a path to earth/ground. Perhaps you are toughing pipework, but even standing on the ground, especially with bare, wet feet as might be the case in a bathroom, then there could be quite a good path to earth/ground.

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For anyone to get electrocuted, electricity has to pass through them.
When we say pass through something, it involves point of entry and point of exit. Same is for current.
Live wire could be source of current entry but we know a bulb or any other load can't function unless and until its other terminal is connected to ground or neutral.
It's same thing.
When birds sit on live wire their whole body become live. And with no ground or neutral touching to them there is no possibility of passing current through them. So they don't feel anything. As the there is no point of exit for the current, the circuit is not complete.

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When a human touches a live wire while in contact with the ground (or another live wire), he completes the circuit and current flows through him. In case of a bird, it is not completing the circuit so it does not gets electrocuted. Though there are some instances when two birds in contact on two live wires get in contact with each other, they get electrocuted as the circuit is completed. If humans could get into contact with a live wire without completing the circuit, even they won’t get electrocuted.

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Voltage doesn't electrocute you, the current flow does. If there is no path to ground you, like a bird on a wire would just rise to the potential of the line. If however you were to put a foot on the ground creating a path for the current to flow you would be electrocuted. Men working on the power lines often work it hot as they call it and by ensuring there is no ground path they are perfectly safe.

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Electricity flows along the path of least resistance. Birds don't get shockedwhen they sit on electrical wires because they are not good conductors of electricity. Their cells and tissues do not offer electrons an easier route than the copper wire they're already traveling along. As a result, the electricitybypasses the birds and keeps flowing along the wire instead. Another reason why electricity will bypass a bird sitting on a wire is because there's no voltage difference in a single wire. Electricity flows from areas of high voltage to areas of low voltage. Electricity flowing through a single power line at 35,000 volts will continue along the path of least resistance and bypass birds. If the bird would touch the ground while sitting on the wire or flap its wings and touch another electric wire with a different voltage, then it would get shocked and likely die by electrocution. This is because its body would become a path for the electricityto reach either the ground (no voltage) or a place with a different voltage(another wire at a different voltage, for example). This is why power lines tend to be high in the air with plenty of space between the wires!