Electricity and Electronics Exam #1

What does the metric prefix "mega" mean and what is its abbreviation?

million 1,000,000 10^6=1e6 Abbreviated with M

What does the metric prefix "micro" mean and what is its abbreviation?

millionTH 0.000001 10^-6=1e-6 Abbreviated with μ (mu)

What is impedance?

more general term for circuits

What does the metric prefix "kilo" mean and what is its abbreviation?

thousand 1,000 10^3=1e3 Abbreviated with k

What does the metric prefix "milli" mean and what is its abbreviation?

thousandTH 0.001 10^-3=1e-3 Abbreviated with m

What is a Leydon Jar?

two metal plates separated by an insulator (glass) used to store charge in attraction between plates (gave scientists a way to store electrical charges). Invented by Musschenbroek

What is a capacitor?

two oppositely charged plates with a wire

What does it mean if two components are in parallel?

two or more components are connected on BOTH SIDES to same pair of nodes

Who is Sir Humphry Davy?

used electrolysis to discover many new elements and explored principles behind voltaic pile. Hired Michael Faraday as his assistant

Can AC and DC behaviors essentially coexist in the same circuit?

yes

What is a solar cell?

"Photovoltaic cell". Device that converts light into electricity through photovoltaic effect.

Who championed AC power over DC?

Benjamin Franklin

What is a Watt?

1Jule/Second

Is a battery or a solar panel in the sun more likely to cause an explosion if you short it out?

A battery. It's a chemical reaction.

What does the I-V curve of an ideal current source look like?

A horizontal line

What is a trivial node?

A trivial node is the junction of two components

What does the I-V curve of an ideal voltage source look like?

A vertical line, because that means the voltage does not change

Who created first voltaic pile (battery)?

Allessandro Volta after discovering Galvani was incorrect about electrical fluid in frog body

What form of power is used in most power delivery networks?

Alternating Current (AC)

Measure of Current

Amps (A). 1A=1C/second 1Amp=1Volt/Ohm I=DQ/DT (change in charge over change in time)

Who found the equation for how a current in a wire creates a magnetic field?

André-Marie Ampére

Who proposed concept of positive and negative charges?

Ben Franklin. Also gave the name battery and defined lighting

Who discovered that there are two kinds of electricity?

C. F. du Fay and Francis Mauksbee the Elder discovered there were two electrical fluids that neutralized each other -- discovery of positive and negative charges.

Measure of Charge (Q)

Coulombs (C)

What form of electricity to batteries provide?

DC

Formula to calculate how much energy is dissipated in circuit over given time

DE=P*t Change in energy=Power*time (in seconds) (answer in Joules)

Passive components

DOES NOT enable one current to control another

Formula to calculate how many coulombs of charge will flow given point in circuit over given time

DQ=I*t Change in charge=current*time (answer in Coulombs)

Who is James Watt?

Developed steam engine

What is voltage?

Electrical Pressure, energy/charge delivered. How much energy it takes to move a volt around the circuit. "energy per unit charge"

Which part of an atom flows easily in metals such as copper?

Electrons

How did the word "electron" arise?

Greek word "Elektron", which is the former word for amber.

Who discovered that there is a connection between electricity and magnetism, and how?

Hans Christian Oersted noticed during a lecture that when electric current of battery was turned off, that the needle of a compass moved from pointing North.

Formula for calculating current

I=V/R (answer in Amps)

Ohm's Law

I=V/R = predict current V=I*R = predict voltage R=V/I = predict resistance

What does it mean if something is linear?

If something has a linear resistance, it means its resistance is not affected by outside factors that could vary, such as temperatures, voltages, etc. Linear resistances are OHMIC.

What does it mean if something is nonlinear?

If something has a nonlinear resistance, it means that its voltage will change based on outside factors such as temperatures, voltages, etc. nonlinear resistances are NON-OHMIC.

What does the I-V curve of a solar cell look like?

Initially horizontal, then becoming vertical

When measuring current directly through component, where should the terminals of the multimeter be?

Inserted in series with the component

Glass and rubber are strong (insulators or conductors)

Insulators

What does the I-V curve of an incandescent light bulb do as it moves toward a higher voltage?

It gets flatter -- the slope decreases.

Who brought together and completed a unified theory of electromagnetic fields?

James Clerk Maxwell brought together four equations that created a completed theory for electromagnetic fields.

Who showed that light is an electromagnetic wave?

James Clerk Maxwell showed that light is an electromagnetic wave through his completed theory for electromagnetic fields.

Who discovered the process of electroplating?

Johann Wilhelm Ritter discovered water could be decomposed by electricity -- collected and measured amounts of hydrogen and oxygen produced in reaction. Discovered process of electroplating (using electric current to dissolve positive ions from metal to create thin coating on electrode)

Who built first electrochemical cell?

Johann Wilhelm Ritter in 1802. 50 copper discs separated by cardboard discs moistened by salt solution

Measure of Energy

Jules (J)

What did Pieter Van Musschenbroek and team invent?

Leydon jar, which is also known as condenser or capacitor. (found in microphones, TVs, phones, computers)

What law did Charles Coulomb propose and experimentally validate? What is the formula?

Like charges repel and opposite charges attract. Formula is F=(kq1q2)/(r^2)

Other common name for magnetite

Lodestone

Who discovered that pairings of different metals cold produce electricity and how?

Luigi Galvani discovered this during his experiment with frog legs -- After sticking various pairs of metal in frogs' legs that caused twitching he concluded that it was a result of "electrical fluid" in frog body.

What did Alexander Neckham do in 1187?

Made a compass

What English physicist built the first dynamo and some of first motors?

Michael Faraday

Who came up with the concept of electric and magnetic fields?

Michael Faraday

Measure of Force

Newtons (N)

Do charges carry their energy independently around a circuit?

No

Measure of Resistance (R)/"Load"

Ohms Ω

What did Theophastus discover?

Other substances have similar magnetic power to amber, which attracted things when rubbed

Valid formula for the power dissipated in resistor

P=(I^2)R

Formula for power dissipation in circuit

P=I*V (answer in Watts)

Fundamental Power Formula

P=I*V=DE/DT(change in energy over change in time)

"Conventional Current Flow Direction" refers to direction flow (or what is effectively the direction of flow) of the ..... (positive or negative charges)

POSITIVE charges

When measuring the voltage across a component, where should the terminals of the multimeter be?

Placed across component (in parallel)

What is the difference between primary and secondary batteries?

Primary -- NON-rechargeable Secondary -- rechargeable

Where are the protons, neutrons, and electrons in an atom?

Protons and neutrons are in the nucleus, electrons orbit on the outside of nucleus in an electron cloud

What happens if wires/conductors get hot?

Resistance goes UP

What does it mean if something is "ohmic"?

Resistance is constant. (If something is non-ohmic, it means the resistance IS NOT constant)

Examples of linear resistors

Resistors, capacitors, inductors (note: capacitors and inductors not used for AC. DC cannot get through capacitor)

Examples of passive components

Resistors, light bulbs, capacitors, inductors, diodes

What is the difference between a shallow cycle and deep cycle?

Shallow cycle -- high current, short time (Small energy) Deep cycle -- moderate current, long time (large energy)

How did term "magnetic" arise?

Shepherd named Magnes, who discovered magnetite while herding sheep because his staff stuck to the rock.

What electricity related device did Otto von Guericke invent?

Static charge generator. Put hand on spinning wheel of sulphur. Helped show existence of electrical attraction and repulsion.

Which Greek philosopher is credited with discovering a key static electricity related effect?

Thales of Miletus discovered the effect of static electricity by noticing that rubbed amber attracted things.

What happens when two charges if they are placed in close proximity to each other?

The force becomes extremely large. If charges are far apart the force is negligible.

What conveys force and energy from an energy source to a load?

The interaction of all charges together

What is power?

The rate of consumption of energy over time, rate of energy delivery/dissipation/absorption of circuit. Measured in WATTS

Who championed DC power over AC?

Thomas Edison

Examples of active components

Transistors, certain vacuum tubes

What is "transient behavior"?

Transitional, behavior that is not steady or cyclical over time

What does it mean if two components are in series?

Two components are connected to same trivial node with NO branches

What did Charles Augustin de Coulomb do in 1776?

Utilized torsion balance to accurately measure force between electric and confirmed that the force was proportional to the product of individual charges and inversely proportional to square of distance between them.

Measure of Voltage

Volts (V) V= 1Joule/Coulomb

What is a node?

Where current splits

In which direction does current flow?

Whichever direction the positive current goes

Who coined term "electricus" and when?

William Gilbert coined "electricus" in 1600 while ordered by Queen Elizabeth to study electrostatics and magnetism.

Who discovered electrolysis?

William Nicholson and Anthony Carlisle discovered water could be decomposed by electricity in 1800

Are "volts", "ohms", "amps", "watts", and "Joules" all named after people?

YES. volts-Allessandro Volta; ohms-Georg Simon Ohm; amps-André-Marie Ampére; watts-James Watt; Joules- James Prescott Joule

Compared to the number 100, are there a large number of electrons in one Coulomb?

Yes

Is a current source or a voltage source designed to provide variable levels of current (within some range)?

a VOLTAGE source

Energy Sink vs Energy Source

an energy sink is when energy goes in a negative direction source is when energy goes into positive

What does the metric prefix "giga" mean and what is its abbreviation?

billion 1,000,000,000 10^9=1e9 Abbreviated with G

What does the metric prefix "nano" mean and what is its abbreviation?

billionTH 0.000000001 10^-9=1e-9 Abbreviated with n

Active components

enable one current to control another. Usually have three terminals. Have control signal and controlled signal.

What is electricity?

flows of charged particles (usually electrons)

Examples of nonlinear resistors

light bulbs, diodes (diodes only let current go one way--DOWN)

Everyday examples of Loads

lightbulb, air conditioner, appliances, TV, washer, dryer, microwave

What is current?

rate of charge flow across cross section