prerequisite: Electrochemical Reactions

Three most basic quantities of electricity are:

• current
• voltage
• resistance

These three quantities can be measured with a multimeter.

Ohm's Law defines the relationships among these three quantities.

\begin{align} voltage &= current * resistance \\ V &= I * R \\ volts &= amps * ohms \\ V &= A * Ω \\ \end{align}

Examples:

• For a motor with a given resistance, increasing the voltage will increase the current.
• If you want to increase the current to the motor, increase the voltage.
• If you choose a motor with a higher resistance, the voltage must be increased to achieve the same current.
• As the resistance is increased, the voltage must be increase to maintain the same current.

Internal resistance between the ears is 100 ohms.

From finger to toe, 500 ohms.

More resistance, more current.

A current of 0.1 amp for 2 seconds can be fatal.

A human has been killed at as low as 42 volts.

Hanging on a wire vs touching the wire and the ground.

Wet skin - 1000 ohms

Dry skin - 500,000 ohms

Length of time. 1 tenth of an amp, 100 mA, for 2 seconds can be fatal.

The human body is an eletro-chemical-mechanical device. A nerve is a kind of conductor. Muscles contract in response to an electrical stimulus.

current - flow of electric charge

electric charge flows when there is voltage present across a conductor

current is measured in amps

current can also be measured as electrons per second

one electron has a charge of 1.602e-19

one ampere = one coulomb per second

one coulomb = 6.242e+18 electrons

one ampere = 6.242e+18 electrons per second

voltage is the force or pressure that causes current to flow in a circuit

voltage is measured in volts

the resistance of a conductor is the opposition to the passage of a current through that conductor

electric charge flows when there is voltage present across a conductor

“voltage present across a conductor”

“flow in a circuit”

“electric charge”1

resistance is measured in ohms

voltage forces charge to flow in a conductor, resistance opposes that force 2

A fourth quantity, power, measured in watts, is a combination of current and voltage.

\begin{align} power &= voltage * current \\ P &= V * I \\ watts &= volts * amps \\ W &= V * A \\ \end{align}

Power is a combination of the force and speed of electrons.

A household lightbulb can be defined by wattage, because household current is a given. In Europe and Asia it is 220VAC.

So a 60 watt light bulb will pull $60w / 220v = .27 amps$.

The three elementary electrical components:

• capacitor
• inductor
• resistor

More:

• transformer
• relay
• switch

A capacitor has two plates separated by a space.

Each plate has area $A$. The plates are separated by distance $d$.

Between the plates is a dielectric material (not to be confused with dialectic).

A dielectric material is an insulator that can be polarised by an electric field. The electrons in the dielectric material cannot drift through the material, but they can shift slightly, causing dielectric polarisation.

The dialectic material has a dialectic constant $ε$.

Wires from a power supply are connected to the plates so that one is positive and the other is negative.

An electric field arises between the plates.

The electric field is measured in volts per meter $V / m$.

Electrical energy is stored in the field.

flux capacity

inductor, induce

The capacitance of a capacitor indicates how much charge the capacitor can store.

Capacitance is measured in farads (F) or microfarads (mF), named for Michael Faraday.

An inductor is a coil.

The coil is wound around a core of dielectric material.

A linear coil is called a solenoidal inductor.

electric “train” made of battery, magnets, coil https://youtu.be/J9b0J29OzAU

electrical circuit - controlled by mechanical switches

electronic circuit - controlled by electronic signals

Wire can be distinguished by size and length.

There are three ways to denote the size of a wire.

1. by gauge, per American Wire Gauge (AWG). (bigger gauge : thinner wire)
2. by diameter, measured in mm
3. by cross-sectional area, measured in $mm^2$, used in EU countries

This wire size chart compares the three systems. https://docs.google.com/spreadsheets/d/1rTeLpV_CcZR8-DhbEExSx8_EGOr-80V_An1KQbldgYc/edit#gid=1590490442

Calculate cross-sectional area from diameter with this equation: $$ A = \frac{D^2 * pi}{4}$$

For wires made of bundled strands, use the same equation but multiply by n numbers of strands.

Light Emitting Diode (LED)

Convert motive power into electrical power.

The first generators were built in the 1830's.

Several types:

• dynamo - uses a commutator to flip the AC to DC, generating a pulsing DC current.
• magneto - generates AC current using permanent magnets
• alternator - generates AC current using field coils

A metal ring split into two halves, with an electrode attached to each halve. Used in motors and in generators.

Regenerative braking - Electric vehicles use the motor as a generator to recharge the battery.

replaced vacuum tube

Types of transistor:

• field effect transistor (FET)
  • metal-oxide-semiconductor FET (MOSFET) - most widely used type
• bipolar junction transistor (BJT)

Force (physics)

• mechanical linear
• mechanical rotational
• electrical
• magnetic

inductance reluctance = resistance conductance

flux force

magnetomotive force vs flux

reluctance = ratio of force to flux in a circuit

circuit, field

reluctance impedance inductance

reluctance R = F / flux ϕ It is sometimes known as Hopkinson's law and is analogous to Ohm's Law with resistance replaced by reluctance, voltage by MMF and current by magnetic flux.

permeance, the reciprocal of reluctance, P = 1/R

in electromagnetism, permeance is the inverse of reluctance a magnetic circuit

 acts as though flux is conducted
 permeance is larger for a larger cross-section of material

in electricity, conductance is the inverse of resistance an electric circuit

  conductance and resistance
  

—–

Triboelectric effect and charge https://www.khanacademy.org/science/physics/electric-charge-electric-force-and-voltage/charge-electric-force/v/triboelectric-effect-and-charge?modal=1

balloon rubbed on the hair, electrons are moving from hair to balloon hair becomes positive, balloon becomes negative

lightening

rubber shoes on carpet, touch doorknob

“charge” positive, negative opposite attract, like repel framework, model protons, electrons

e = charge of a proton -e = charge of an electron

coulomb 1C ~= 6.24 * 10^18e e = 1.60 * 10^-19C reciprocal

https://www.khanacademy.org/science/physics/electric-charge-electric-force-and-voltage/charge-electric-force/v/coulombs-law?modal=1

1785 Charles Augustin de Coulomb

Coulomb's law of electrostatic force

\begin{align} F_e &= K_e \frac{|q_1q_2|}{r^2} &&\text{electrostatic force}\\ \text{where:}\\ q_1 &= \text{charge 1} \\ q_2 &= \text{charge 2} \\ r &= \text{distance between charges} \\ K_e &~= 8.987551 * 10^9 * Nm^2 / C^2 &&\text{electrostatic constant} \\ &&&\text{resulting units Newton meter squared / coulomb squared} \\ \end{align}

Analogous to Newton's Law of Gravity

\begin{align} F_G &= G m_1 m_2 / r^2 &&\text{force of gravity} \\ G &~= 6.674×10^−11 m^3⋅kg^−1⋅s^−2 &&\text{gravitic constant} \\ \end{align}

q_1 &= +5 * 10^3 C
q_2 &= -1 * 10^-1 C
r &= 0.5m
\end{align}

voltage drop across a component
the entire voltage is dropped across the whole circuit
resistors wired in series share the voltage drop proportionate to the resistance in ohms

• standard - produce electricity in a single phase
• invertor - produce electricity in three phases, invert to DC, invert back to more stable
• AC
• induction (asynchronous) -
• synchronous -
• brushed - produce AC with sine wave fairly close to grid wave
• brushless - use electromagnetic induction instead of mechanical brushes

mirror image

• induction
• brushed
• brushless
• AC
• DC
• single phase
• 3-phase

any two different kinds of metal can be placed in a conducting solution and you get a battery.

copper and zinc strips into a lemon or a potato

soda can, the soda from the can, and some copper.

Zinc copper soda

https://en.m.wikipedia.org/wiki/Battery_balancing Battery balancing and battery redistribution refer to techniques that improve the available capacity of a battery pack with multiple cells (usually in series) and increase each cell's longevity.[1] A battery balancer or battery regulator is an electrical device in a battery pack that performs battery balancing.[2] Balancers are often found in lithium-ion battery packs for laptop computers, electrical vehicles. etc.

state of charge (SOC)

Balancing is only necessary for packs that contain more than one cell in series.

Parallel cells will naturally balance since they are directly connected to each other,

but groups of parallel wired cells, wired in series (parallel-series wiring) must be balanced between cell groups.

Active balancing passive balancing

Bottom balancing top balancing

Balancing while not charging

https://youtu.be/OjGAvbULBH8 Battery pack with BMS made for three lithium ion cells Thin wires for balancing thick wires for carrying current

Thickness 0.10, 0.12, 0.15, 0.20 mm Width 5, 8, 10 mm

Student make battery https://sciencing.com/making-wet-cell-battery-4781656.html

AC vs DC: ohm's law applies equally unless there is a capacitance or an inductance in the circuit.

Faraday Lenz Franklin

Voltage drop http://wiresizecalculator.net/calculators/voltagedrop.htm

Inductor ac vs dc https://www.homemade-circuits.com/inductors-in-acdc-circuits-explained/

induction = asynchronous an induction motor can be used as a generator and vice-versa an induction machine is both a generator and a motor induction is for AC only is induction always three-phase AC? 1. start with induction motor attached to the AC input line 2. apply a torque to the rotor to bring it up to match the speed of AC input line, the synchronous speed, current falls to zero 3. speed up the rotor past the synchronous speed, reverse current is generated

synchronous and induction generators are both alternators

https://www.homemade-circuits.com/inductors-in-acdc-circuits-explained/

inductors and capacitors are often used together. they are complementary.

inductor and capacitor and battery all store electric energy

inductor stores energy in the form of magnetic energy

inductor capacitor inductor | initial energy stored | energy released after | capacitor | energy stored gradually | when is energy released?

an inductor in AC == a resistor in DC

inductor in DC: behave and produce a short across inself in AC: offer an opposing or restricting response, aka “choke”

suppressing high frequencies, suppressing surge currents, for bucking or boosting voltages

inductance: the property of opposiing instantaneous current reactance: the magnitude of this opposing force, proportional to frequence and current

made of coils or turns of wire

https://theelectronicshobbyblog.com/2019/03/25/beginners-corner-inductors-in-dc-circuits/

inductor - stores energy in a magnetic field capacitor - stores energy in an electric field

https://electronicsphysics.com/faradays-law-of-electromagnetic-induction-for-emf/ this author uses the verb “induce” incorrectly

Oersted: current carrying wire produces magnetic field around it Biot-Savart law, Ampere's circuital law, Fleming's right hand thumb rule, Maxwell's corkscrew rule

the reverse is also true

a current is induced in a conductor in a varying magnetic field Faraday's law of electromagnetic induction induced EMF electromotive force (EMF) the EMF can drive a current

faraday law 1 Whenever a conductor is placed in a varying magnetic field, an electromotive force is induced. If the conductor circuit is closed, a current is induced, which is called induced current. Note: the EMF is a potential. The current is actual.

faraday law 2 - calculate the magnitude of the induced EMF e = N × dΦ / dt

Lenz's Law e = -N × dΦ / dt Add minus sign. The polarity of induced EMF is such that it would produce a current which opposes the change in magnetic flux that produced it. Φ = change in magnetic flux t = time N = Number of turns e = EMF

flux → change in flux → EMF
https://youtu.be/Y2XvIofbwpc

electromagnetic induction https://en.wikipedia.org/wiki/Electromagnetic_induction directly proportional to number of turns/coils in the conductor variance. moving the field or the conductor. using AC.

analogies Lenz's law may be seen as analogous to Newton's third law in classical mechanics[2][3] and Le Chatelier's principle in chemistry.[4]

laws: qualitative vs quantitative (equation ?)

difference between magnetic and electric circuit https://circuitglobe.com/difference-between-magnetic-and-electric-circuit.html table

AC to DC Rectifier plus capacitor

Tesla model S induction motor conventional well-proven Squirrel cage rotor 3% inefficiency Model 3 Ipm sim rm Magnetic and reluctance action Four permanent magnets on rotor RMF rotating magnetic field, can be DC 2 phase or three phase PM motor Good starting torque Back EMF at high speeds Synchronous reluctance motor SynRM Good at high speeds, No back EMF

Combined PM and SynRM

3 phase ac power to the stator Produces a rmf A 4 pole Rmf Induces current on the rotor bars

In an induction motor The rotor speed always lags behind the rmf Rotor speed < rmf speed

No brushes No permanent magnets Speed depends on the frequency of the ac power supply Variable frequency drive - controls motor speed From 0 to 18,000 RPM

Jan 14 10 am

three-phase induction motor - has three separated pairs of coils in the stator

The stator generates an RMF.

The shaft is connected to the rotor.

Squirrel cage rotor - Two end rings connected by some bars, resembling a hamster wheel.

The squirrel cage is effectively a set of wire loops. The RMF generated by the stator induces a current in each of the wire loops of the squirrel cage. The current in each wire loop generates a magnetic field. This magnetic field in the rotor interacts with the magnetic field in the stator resulting in rotation.

Induction, four types

electrostatic - a redistribution of electric charge in an object, caused by the influence of nearby charges

Electromagnetic induction - Current in a wire generates/produces/creates/induces a magnetic field around the wire.

Electric induction - a changing magnetic field induces a current in a nearby conductor.

Magnetic induction - is the process of magnetization of materials in an external magnetic field. (Same as electrostatic ?)

One of the four fundamental forces in the universe is the electromagnetic force. Not the electrical force or the magnetic force, but the electromagnetic force.

Can a battery drive a three-phase ac motor?

In north America, split phase system.

Variable frequency drive (VFD) Rectifier - 3 phase ac to pulsed dc, 6 diodes DC bus - smooth dc, capacitor Inverter - DC to ac pwm, igbt's

Insulated-gate bipolar transistor - https://m.youtube.com/watch?v=yEPe7RDtkgo

Potentiometer - variable resistor

PWM Control lighting control motor speed create efficient power supplies

Also used to send data Tv remote control

Also used in audio amplifiers 99% efficient, as opposed to 25 to 50% efficiency of non pwm amplifiers

Switching frequency Duty cycle

Average voltage, perceived power

Use PCM to control lighting The flicker fusion rate in the human brain is 18 times per second Frequency 100 times per second Duty cycle 25%

Older systems use DC voltage control By placing a variable resistor in the circuit Excess energy wasted as heat, always the same current regardless of dimming More narrow range of variability Smoother power delivery

The PCM used for servos is different Position of a servo Acceleration of an esc

Between 1000 and 2000 microseconds

555 IC

The pulse wave is a square wave meaning it has a low and a high value meaning it can be used to represent binary data.

Torque ripple

Applications Rooftop ventilation fan Elevator Drone propeller Electric motorcycle Robotic elbow DIY generator DIY motor

Rectifier | ac to dc Inverter | DC to ac Transformer | ac to ac Converter | DC to DC

Any motor becomes a generator if you spin it.

AC and DC generators, animation https://www.khanacademy.org/science/in-in-class-12th-physics-india/in-in-electromagnetic-induction/x51bd77206da864f3:ac-generator/v/ac-dc-generator brushes and slip rings = AC generator brushes and split rings = commutator = DC generator

three phase generator, motor six wires I get, three wires, 9 wires, 12 wires I don't get

https://m.youtube.com/watch?v=K8Ir1-COjnc&t=0s In a balanced three phase generator the fourth wire the neutral wire will have zero current and therefore it can be removed.

radial flux vs axial flux - orientation of the coil windings in the stator

Bldc and pmsm are both synchronous and both use permanent magnets

permanent magnet Synchronous machine (PMSM)

Differentiation: shape of back emf voltage

https://components101.com/diodes/5mm-round-led

Anode - Positive terminal of LED

Cathode - Negative terminal of LED

symbol

direction of current

• Elevator (industrial)
• Drill ac (household)
• Drill dc
• Quadcopter
• Motorcycle
• Car

servo - robotic elbow

stepper -

Multimeter

Oscilloscope

Clamp Meter

voltage vs emf vs flux https://www.khanacademy.org/science/in-in-class-12th-physics-india/in-in-electromagnetic-induction/x51bd77206da864f3:ac-generator/v/emf-flux-equation-graph-of-ac-generator

there is no such thing as a dc motor

Servo = DC motor Gear box Potentiometer Circuit board

Gearbox step down rpm, increase torque Output of gearbox connects to potentiometer Closed loop - potentiometer turns 180 degrees Open loop - potentiometer turns 360 degrees

Syllogism vs dialectic

Eletromagnet vs permanent magnet.

Often a permanent magnet is painted,
so the south pole is blue,
and the north pole is red.

South pole is positive.
North pole is negative.

Earth's north is actually south

Electromagnet also has poles.
Fleming's right-hand-rule.
http://kitbook.com/electromagnet-poles/

battery plus to solenoid, wrap clockwise, starting at south pole,
https://www.youtube.com/watch?v=n63DAWvaHlk

letter N is counter-clockwise arrow symbol
look at the north pole of the magnet
current will be going thru the coil counter-clockwise

letter S is clockwise arrow symbol
look at the south pole of the magnet
current will be going thru the coil clockwise

A generator produces AC.

A battery produces DC.

AC does not have positive and negative.

AC has hot and neutral.

great animations of magnetic fields https://www.youtube.com/c/Physicsandanimation

A battery has two terminals, positive and negative. Between the two terminals is an electrolyte.

Chemistry. A charged battery has a buildup of extra electrons at the negative terminal.

When a circuit is completed, the extra electrons flow from the negative terminal to the positive terminal, until the two terminals are balanced, and the battery has lost its charge.

When scientists first started working with electricity, they did not know about protons and electrons.

making batteries,

Electronic engineers say electric current is the flow of electrons from negative to positive.

Stubborn electrical engineers say current is the flow of a positive “space” from positive to negative. They call this “conventional” current or positive current. I call this wrong.

Conciliatory persons say there are two simultaneous currents: negative bits flow one way, and positive bits flow the opposite way.

Consider a queue of persons waiting in line for ice cream. When the person at the counter is served he moves away leaving a space. The next person in line moves forward to the space at the counter, leaving a space behind him. The person behind him steps forward to fill the space. And so on with each person back to the end of the line.

In this example, what is moving: the people, or the space?

some of the excuses I have heard.

• Too hard to change now. Like telling Americans to drive on the left, there would be chaos.
• It doesn't matter mathematically in circuit analysis. (not true for batteries, transistors and diodes)
• There are two simultaneous and opposite circuits: the electrons flow from negative to positive, the positive charge flows from positive to negative. (False)

Ben Franklin is often blamed for the mixup, because he described positive and negative charges 50 years before the first battery, and 150 years before the electron was discovered.

Animation of ice cream queue. Circuit drawings: battery, LED. Two drawings, electron and “conventional”.

right-hand rule
first-finger gives direction of the flux
second-finger gives direction of the current
which current is this? electron or conventional He decided that the glass rod being rubbed with silk would be a positive charge while the rubber and fur would be a negative charge. So, with that convention, by removing electrons, the glass rod became positively charged and by adding electrons, the rubber rod became negatively charged.

• 1752 Ben Franklin flew his kite in a storm and captured electricity from lighting. He described positive and negative charges.
  • Rubbing a glass rod with silk produces a positive charge.
  • Rubbing rubber with fur produces a negative charge.
• 1800 Alessandro Volta invented the first battery, the voltaic pile. https://www.liquisearch.com/alessandro_volta/first_battery
  • zinc: negative electrode
  • copper: positive electrode
  • saltwater: electrolite
• 1861 Maxwell presents his equations (right-hand thumb rule?)
• 1897 J.J. Thomson discovers the electron, described it as a negatively charged particle floating in a sea of positive charge, like plums in a pudding, the “plum pudding model”
• 1909 Rutherford discovers the nucleus in the gold foil experiments and develops the planetary model
• 1913 Niels Bohr discovers the specific energy levels of electrons in the atom
• 1940 US Navy begins training electronics engineers using the electron current.
• 1945 John Ambrose Fleming dies

Battery
two terminals marked + and -
Is that true? Does the - terminal really have a superfluence of electrons? annode, cathode

chemical reactions:

• oxidation = loss of electrons
• reduction = gain of electrons

anion - has gained an electron, negative charge cation - has lost an electron, positive charge

cathode - reduction occurs,

anode - oxidation occurs, anions give off electrons, negative charge

species?

electrons flow from anode to cathode, from oxidation half to reduction half

inside the battery, electrons flow from positive to negative inside the battery outside the battery, from negative to positive

flow is reversed by a battery charger, something with a bigger voltage

, AAA, AA, C, D dry cell

The electrolyte helps transport ions between positive and negative electrodes.

Numerical Error with Simulation…
https://physics.stackexchange.com/questions/139479/numerical-error-with-simulation-of-electric-charge-in-homogeneous-magnetic-field

Mathematical Model of Magnetic Field Lines
https://spacemath.gsfc.nasa.gov/earth/9Page23.pdf