Chapter 2 Electronics Fundamentals: Charge, Voltage, Current & Resistance

What does the Bohr model illustrate?

The atomic structure, with a positively charged nucleus containing protons and neutrons, and negatively charged electrons orbiting in discrete shells.

What defines the atomic number of an element?

The number of protons in the nucleus.

What is a valence shell?

The outermost electron shell of an atom, containing valence electrons crucial for chemical reactions.

How many valence electrons do metals typically have?

One, two, or three, making them good conductors.

What is the significance of valence electrons?

They determine an atom's electrical and thermal conductivity.

What is the behavior of like and unlike charges?

Like charges repel each other, while unlike charges attract each other.

What is the relationship between the force of electrical charges and distance?

The force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

What is voltage?

The work done per unit of charge to move that charge against an electric field, also known as electromotive force (EMF) or potential difference.

What is the equation for voltage?

V = W/Q, where V is voltage in volts, W is work done in joules, and Q is charge in coulombs.

What is one volt defined as?

The potential difference when one joule of energy is used to move one coulomb of charge.

Name common sources of voltage.

Batteries, solar cells, fuel cells, and generators.

How do batteries work?

They store chemical energy, which is converted into electrical energy when an external path is provided for the chemical reaction.

What is the difference between batteries and fuel cells?

Batteries store energy and can be recharged, while fuel cells require a continuous supply of reactants to produce electricity.

What is current?

The rate of flow of electrical charge, measured in amperes (A).

What is the equation for current?

I = Q/t, where I is current in amperes, Q is charge in coulombs, and t is time in seconds.

What is the definition of one ampere?

The flow of one coulomb of charge per second.

What are the two conventions for current direction?

Conventional Flow (positive to negative) and Electron Flow (negative to positive).

What is resistance?

The opposition to the flow of current, measured in ohms (Ω).

What is Ohm's Law?

The relationship expressed as V = IR, where V is voltage, I is current, and R is resistance.

What is conductance?

The reciprocal of resistance, representing how easily current flows, measured in siemens (S).

What are resistors?

Components specifically designed to provide a certain amount of resistance in a circuit.

What do the color bands on a four-band resistor indicate?

The resistance value and tolerance.

What does the first band on a four-band resistor represent?

The first digit of the resistance value.

What does the second band on a four-band resistor represent?

The second digit of the resistance value.

What does the third band on a four-band resistor represent?

The multiplier (the power of 10 to multiply the first two digits by).

What does the fourth band on a four-band resistor represent?

The tolerance (the allowable percentage variation from the stated value).

What is the resistance value of a resistor with Gray, Red, Black, Gold bands?

82Ω ±5%

What does 'R' signify in alphanumeric labeling of resistors?

Ohms (Ω).

What does 'K' signify in alphanumeric labeling of resistors?

Kilo-ohms (10^3 Ω).

What does 'M' signify in alphanumeric labeling of resistors?

Mega-ohms (10^6 Ω).

What is a potentiometer?

A three-terminal variable resistor used to vary voltage.

What is a rheostat?

A two-terminal variable resistor used to vary current.

What factors determine the resistance of a conductor?

Material, length, and cross-sectional area.

What is the formula for wire resistance?

R = ρ(l/A), where R is resistance, ρ is resistivity, l is length, and A is cross-sectional area.

What are the three fundamental components of a basic electric circuit?

Voltage source, path (conductors), and load.

What is the purpose of a switch in a circuit?

To control the flow of current by opening or closing the path.

What does SPST stand for?

Single Pole, Single Throw.

What does DPDT stand for?

Double Pole, Double Throw.

What is a Digital Multimeter (DMM)?

An instrument capable of measuring multiple electrical quantities, such as voltage, current, and resistance.

What is an Analog Meter (VOM)?

A device that measures voltage, current, and resistance using a moving needle on a calibrated scale.

What is an Ampere (A)?

The unit of electrical current.

What is a Coulomb (C)?

The SI unit of electrical charge.

What does the term 'Ground' refer to in a circuit?

A common or reference point in a circuit, often considered to be at zero potential.

What is the unit of electrical resistance?

Ohm (Ω).

What is the unit of voltage?

Volt (V).

What does Conductance (G) measure?

The ability of a circuit to allow current, measured in Siemens (S).