what is 1 volt and 1 ampere? May sounds very basic but its deep. please help

Question

Facts:

1. Charge, or more specific electric charge, on 1 electron is \$-1.6 \times 10^{-19}\$ Coulomb
2. One has to do some work to get electron from its outer most orbit. It can be room temperature as well.
3. Current flows only if there is potential difference.

Questions:

1. Ampere is defined as, 1A = 1C/1sec
2. My understanding is : “We can say 1A is flow of electric energy of \$(6.242 \times 10^{18} )\times (1.6 \times 10^{-19})\$ Coulomb = 1C in 1sec from cross section.” To generate this flow of electron, we need some energy. What is this energy? Is it volt?
3. Volt is defined as, 1V = 1J/1C
4. My understanding is : As mentioned in fact-2, one has to do some work to get electron from its outer most orbit and same electron will help to generate current. So, here we are doing 1J of work to get \$6.242 × 10^{18}\$ electrons (which has accumulative electric charge of 1C) out of their outer most orbits. If one says, free electrons are already there in conductor, then where are doing 1J of work.
5. With above details, how can we define potential difference.
6. Very basic, may be dumb as well, if electron pass through LOAD, Say bulb, will it loose its charge of \$-1.6 x 10^{-19}\$ Coulomb. If not, from which energy bulb is able to glow.

please help in building clarity.

Answer 1

Facts corrected:

1. Charge of 1 electron is \$-1.6 \times 10^{-19}\$ Coulomb.

2. The single electron in the valence shell (fourth shell) of Copper (for example) is far from the nucleus (in atomic terms) and it can become a free electron with the application of little external energy. You just have to overcome the attractive energy of 1 proton. This energy can be Electromotive Force, heat, light, etc.

3. Loss of one electron by atom, create a positive ion. All atoms want to be neutral.

4. Current flows only if there is source of Electromotive Force and a complete circuit.

Questions:

The source of energy which causes electrons to be free is Electromotive Force, measured in Volts. EMF causes free electrons, \$Cu^+\$ ions attract free electrons, repeat. Individual electrons may move small atomic distances, but current is the net flow of electrons. Current is just the flow of electrons from atom to atom.

1A is defined as 1 C/s. If you can get \$6.242 × 10^{18}\$ electrons to move through the cross section of wire in 1 second, 1 A of current flows. 1/2 a second, 2A.

Fact 1 says charge of 1 electron is \$-1.6 \times 10^{-19}\$ Coulomb. It cannot lose this charge. It is what defines it. As it moves through a lamp, it creates heat. The heat in the lamp, creates light. Power in 1 W = 1 J/s.

So the energy lost to Cu wire is small compared to energy required to force electrons through a resistive lamp made of nichrome (alloy of nickel, chromium and iron) (Resistivities @20°C, Cu: \$1.72 \times 10^{-8} Ω \cdot m \$; and nichrome: \$100 \times 10^{-8} Ω \cdot m \$). Losses would be proportional to each components resistance.

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EMF and volt. As you mentioned EMF is the one which causes free electron. How can we guide this free electrons to move in specific order. While clarifying this can you please explain what is voltage and what is the difference between EMF and voltage. What is potential difference? Thank you very much in advance.

The negative terminal of a source (battery) can be considered a bucket of electrons. Likes repel, so electrons are forced away from negative terminal. Similarily, opposites attract, so positive terminal attracts free electrons. Electron Flow Current is the name for electrons moving from - terminal to + terminal. That is the reality. Conventional current (named to reflect the opposite to Electron Flow) was postulated during the discovery of electricity, where the carriers are positive and current flows from + to -.

This explaination for DC works with ac, just that current reverses 120 times a second for 60Hz.

EMF is a source of potential difference, which when applied a circuit is consumed by the components. In a battery, a chemical reaction takes place, where electrons are removed from positive terminal and held on negative terminal. If it is an alkaline battery, the negative terminal has a potential of -0.75V and the positive terminal +0.75V. The potential difference is +0.75V - (-0.75V) = 1.5V. We commonly do not use potential difference, but rather just voltage. The battery has 1.5V.

When a source is applied to a circuit, the potential is consumed by the components. If we apply 1.5V, the circuit consumes the 1.5V. All of the voltage drops in the circuit will add up to 1.5V. Either way, we call EMF and voltage drops, just voltage.

Aside from that, as Tony says, ignore the physics and deal with V, A and Ω. The metric system allows you to go to compatible units, but it is easy to become confused.

Answer 2

• All dielectrics hold a polar charge voltage. Q=CV (Also all dielectrics are insulators and visa versa)
• All conductors conduct a charge and the voltage depending on current flow and resistance. V=IR.

Do not confuse the two as these are separate characteristics.
So a bulb cannot hold a charge since it is a conductor and not a dielectric, but it may conduct a flow of charges = current.

The flow of charges I = dQ/dt is the rate of charge, Q per second [Coulombs/s]
However a simple conductor I=V/R is linear and a capacitor, C has a current I=CdV/dt depends on the rate of voltage change.

Thus Capacitor voltage change is the "integral" of current over time.

• Conductors with resistance, R dissipates power. The energy is the product with time.
• The energy dissipated in a conductor is E=Pt = IR*t [Joules=Watt-seconds].
• The energy stored in a dielectric capacitor is Ec= ½CV²
• The energy stored in an Inductive conductor, L is E=½LI²

For AC current, Capacitors, C has an impedance (Z(f) somewhat like resistors but lagging in phase for current by 90 degrees. \$Z_C=\frac{1}{\omega C}\$

You need not get into the physics of orbital electrons bumping into each other like a wave of hands around a stadium unless you really want to go on that tangent. But first get a good grasp on the physics.

Answer 3

Charge, or more specific electric charge, on 1 electron is −1.6×10−19 Coulomb

OK.

One has to do some work to get electron from its outer most orbit. It can be room temperature as well.

Not really in metals. Their outer electrons are so weakly attracted to their specific nuclei, that they tend to drift around randomly within the body of the metal. It only requires a little shove to convert that random movement into a slow drift in your chosen direction.

But it may be true in semiconductors and other sorts of conductors.

Loss of one electron by atom, create a positive ion. All atoms want to be neutral.

When current is flowing through a metal wire, electrons aren't really lost. For every electron that leaves one end of a given stretch of wire, a new one comes in at the other end to replace it. So you don't end up with any ions. Other conductors (such as tanks of salty water) may be more complicated.

Current flows only if there is potential difference.

Yes, except in a superconductor. They are such perfect conductors that once you start the electrons moving, they keep going.

Ampere is defined as, 1A = 1C/1sec

OK.

My understanding is : “We can say 1A is flow of electric energy of (6.242×1018)×(1.6×10−19) Coulomb = 1C in 1sec from cross section.” To generate this flow of electron, we need some energy. What is this energy? Is it volt?

Voltage isn't energy. It's a potential. The difference is subtle, but is clear in the next equation. An electron at a high voltage is a bit like a rock at the top of a hill feeling the pull of gravity - the pull is trying to drag it down to a lower potential.

Volt is defined as, 1V = 1J/1C

So if you have a 1V cell, and you allow 1C of electrons to flow from one terminal to the other, they will release 1J of energy in doing so.

My understanding is : As mentioned in fact-2, one has to do some work to get electron from its outer most orbit and same electron will help to generate current. So, here we are doing 1J of work to get 6.242×1018 electrons (which has accumulative electric charge of 1C) out of their outer most orbits. If one says, free electrons are already there in conductor, then where are doing 1J of work.

For a simple current running through a wire, this isn't relevant. It might be when getting LEDs to glow, though.

With above details, how can we define potential difference.

The potential difference is the difference in voltage between two points. It's not actially even possible to measure the voltage at one point; you have to measure it between two points. In the analogy of the rock at the top of the hill, it's like the height of the hill.

Very basic, may be dumb as well, if electron pass through LOAD, Say bulb, will it loose its charge of −1.6x10−19 Coulomb. If not, from which energy bulb is able to glow.

Electrons don't lose their charge. All electrons have the same charge. What they are losing is their potential. Like the rock rolling down the hill - it's still the same rock when it's at the bottom of the hill. the only difference is that it's now lower down.