# Kaplan- Lesson 6: Electical Systems Flashcards

The three basic factors in electricity are…

potential, current, & resistance

Potential electricity is measured in…

voltage (volts)- V

Current electricity is measured in….

amperes (amps)- I

Resistance electricity is measured in…

ohms (Ω)- R

What is Ohm’s Law?

The formula that relates the three factors of electricity.

I = V / R

I= current V= voltage R= resistance

What is direct current?

current that flows only in one direction with constant voltage.

Equation for power in Direct Current (DC) circuit is….

P = V x I

P= power V= voltage I= current

What is alternating current?

based on the concept that electricity has no inertia, and therefore the direction of the flow can be reversed very rapidly by reversing the voltage.

Equation for power in a single-phase circuit is…

P = V x I x PF

P= power V= voltage I= current PF= power factor in decimal form

Equation for power in a three-phase circuit is…

Same as single-phase but multiply by the √3

P = V x I x PF x √3

P= power V= voltage I= current PF= power factor in decimal form

A wire wound spirally around an iron core to produce a magnetic field and that is used as an electromagnetic switch is called?

A solenoid

The most basic form of power generation is…

a single-phase alternator

What is the typical AC power frequency in the US and what is the most common household voltage?

60 hertz

110 volts

Devices that change the voltage of an AC circuit to a higher or lower value are called ______.

Transformers

How does a transformer work?

A transformer consists of an iron core on which two separate coils of wire are wound. The coil with the greater number of turns will have a higher voltage.

A primary winding is the winding that is used for ____ in a transformer, while the secondary winding is used for ____.

Input; output