Basic Electrical Principles & Safety

Flashcards covering basic electrical principles, atomic structure, magnetic fields, current flow, energy conversion, carbon monoxide safety standards, and lockout/tagout procedures.

What did Andre Ampere discover regarding the magnetic field strength around a current-carrying wire?

He proved that the strength of the magnetic field rises with increasing current and decreases with the distance away from the wire.

How does coiling a current-carrying wire affect its magnetic field?

Coiling the wire increases the strength of the magnetic field.

How does a clamp-on ammeter measure electrical current in an AC conductor without direct contact with the wire?

It measures the current by clamping around a single conductor to detect the encircling magnetic field produced by the current.

What is the definition of an atom?

An atom is the smallest particle that an element can be reduced to and still maintain the properties of that element.

What are the three principal parts of an atom?

The electron, neutron, and proton.

What is an element?

An element is a substance that cannot be chemically broken down and contains atoms of only one variety.

What is a compound?

A compound is a combination of the atoms of two or more elements.

What is the OSHA 8-hour average limit for carbon monoxide in an enclosed space?

$50\,\text{PPM}$ ($0.005\%$).

What carbon monoxide concentration causes dizziness, nausea, convulsions, and death within 2 to 3 hours?

$800\,\text{PPM}$.

What is the valence shell of an atom?

The outermost shell of an atom, which is the reactive shell where atoms can add or give up electrons.

How many valence electrons distinguish conductors, insulators, and semiconductors?

Conductors have $3$ or less valence electrons, semiconductors have $4$ valence electrons, and insulators have $5$ or more valence electrons.

How many valence electrons does a copper atom have?

One electron in its valence shell.

What is static electricity?

Static electricity is an electrical charge at rest.

How fast does a single electron move in a conductor compared to the speed of the electrical chain reaction?

A single subatomic particle moves slowly at about one-half inch per second ($0.5\,\text{in/s}$), while the chain reaction moves at about the speed of light ($186,000\,\text{miles per second}$).

What are the four best natural conductors of electricity in order of effectiveness?

Silver (the best natural conductor), followed by copper, gold, and aluminum.

How many electrons are in one Coulomb?

$6.25 \times 10^{18}\,\text{electrons}$.

How is an Ampere defined mathematically in terms of charge and time?

$\text{Ampere} = \frac{\text{coulomb}}{\text{second}}$.

What letter represents current in electrical formulas?

The letter $I$.

What are the six methods by which voltage can be produced?

Electromagnetism (generators), chemicals (batteries), light (photocells), heat (thermocouples), pressure (piezoelectricity), and friction (static electricity).

What is the key difference between DC and AC current flow?

DC (Direct Current) flows in one direction with positive ($+$) and negative ($-$) polarity, while AC (Alternating Current) alternates back and forth.

What are the functions of a rectifier and an inverter?

A rectifier converts AC to DC for equipment requiring DC, while an inverter converts DC to AC.

Into what five forms of energy can electrical energy be converted?

Sound (speakers), rotary motion (motors), light (lamps), linear motion (solenoids), and heat (heating elements).

What is the conversion factor to convert Watt-hours (Wh) to British thermal units (Btu)?

Multiply $\text{Wh}$ by $3.412$.

What condition is required to produce pure white light across the visible spectrum?

Pure white light is produced only when energy across the entire spectrum is approximately at the same energy level.

What are the nine steps of the Lockout/Tagout safety procedure in sequence?

1. Identify, 2. Notify, 3. Turn off, 4. Isolate, 5. Lock out, 6. Test, 7. Return controls to off, 8. Work, 9. Remove locks.

Which standards govern the calculation and requirements for Arc Flash hazard protection?

IEEE 1584 (Guideline for performing arc flash hazard calculations) and NFPA 70E.