Electrical Theory & Fundamentals Flashcards
9 cards from real Licensed Electrical Contractor practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 9 Electrical Theory & Fundamentals flashcards as text
What is the relationship between voltage, current, and resistance?
Answer: Voltage equals current multiplied by resistance.
This relationship is known as Ohm's Law, a fundamental principle in electrical engineering. It states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, with the constant of proportionality being the resistance (R), expressed as V = I * R.
What is the unit of electrical resistance?
Answer: Ohms.
Ohms (Ω) are the standard unit of electrical resistance, named after Georg Simon Ohm. Resistance measures how much a material opposes the flow of electric current, and it is a crucial factor in determining current flow and voltage drop in an electrical circuit.
Which of the following best describes an electrical circuit?
Answer: A path that allows current to flow from a power source to a load and back to the source.
An electrical circuit is a complete, closed loop that enables electric current to flow continuously. It consists of a power source (like a battery or generator), conductors (wires), a load (a device that uses electricity), and a return path, ensuring the uninterrupted circulation of electrons.
What is the purpose of a capacitor in an electrical circuit?
Answer: To store and release electrical energy.
A capacitor is a passive electronic component that stores electrical energy in an electric field between two conductive plates separated by a dielectric material. It can then rapidly release this stored energy, making it useful for filtering, timing, and power conditioning in various electronic circuits.
What is the function of an inductor in a circuit?
Answer: To resist changes in current and store energy in a magnetic field.
An inductor is a passive electrical component that stores energy in a magnetic field when current flows through it. Its primary function is to oppose changes in the current flowing through it, a property known as inductance, which makes it useful for filtering, tuning, and energy storage in AC circuits.
What is the purpose of a transformer in an electrical circuit?
Answer: To change the voltage level in an AC circuit.
A transformer is a static electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. Its main purpose is to step up or step down AC voltage levels, allowing for efficient transmission of electricity over long distances and adaptation to different load requirements.
Which of the following describes the power factor of an electrical circuit?
Answer: The ratio of real power to apparent power.
Power factor is a measure of how effectively electrical power is being converted into useful work in an AC circuit. It is defined as the ratio of real power (the power actually consumed by the load) to apparent power (the total power supplied), indicating the efficiency of power utilization.
What is the main difference between alternating current (AC) and direct current (DC)?
Answer: DC flows in one direction, while AC changes direction periodically.
The main difference between alternating current (AC) and direct current (DC) lies in their direction of flow. DC flows in one constant direction, typically from a positive to a negative terminal, whereas AC periodically reverses its direction of flow and continuously changes its magnitude, which is standard for power grids.
Which of the following is the unit of electrical power?
Answer: Watts.
Watts (W) are the standard unit of electrical power, representing the rate at which electrical energy is consumed or produced. One watt is equivalent to one joule per second, and it is calculated as the product of voltage and current in a DC circuit, or real power in an AC circuit.