Basic Electricity Flashcards
One kilowatt is equal to how many watts?
1,000 watts
What law describes the most fundamental or basic relationship and electrical circuit? 
Ohms law 
What are the three elements of ohms law?
Voltage current and resistance
How would you write ohms law as an equation?
E = I x R
If the resistance in a DC circuit remains the same, but the voltage doubles, what happens to the amount of current flowing through it 
It also doubles
In DC circuits what unit measures power?
Watts
What three elements are required to form an electrical circuit
A source of electrical energy, a load or resistance to use electrical energy and wires or conductors to connect the source to the load
What is the definition of a short circuit?
An unintentional low resistance path between a component/conductor to ground
DC circuit can take on of three forms or types. What are they?
Series, parallel, and series/parallel or complex
Name the sources of electrical energy
Thermal, light, pressure, magnetism, and chemical
Describe a capacitor
Two parallel plates, separated by dielectric
Fully charge lead acid battery has a specific gravity that varies between what two values
1.275 and 1.300
A 24 V lead acid battery has how many cells
12
What tool is used to measure the density of the electrolyte in the lead acid battery?
Hydrometer
You must apply a correction to the specific gravity reading of the electrolyte of a lead acid battery when the temperature is outside of what two values
Whenever the temperature is less than 70°F or more than 90°F
What is the reason for having separate facilities for storing and servicing nickel cadmium and lead acid batteries?
The electrolyte in the two types of batteries is chemically opposite, and the fumes from one type can contaminate the electrolyte of the other type
The charge of a nickel cadmium battery cannot be determined by measuring the specific gravity of electrolyte, for what reason
There is no significant change in the specific gravity of the electrolyte, as the battery is charged or discharged
What is the principal advantage of AC current over DC current
Power can be transmitted over long distances, more efficiently, and with smaller wires, because the voltage can be easily increase or decrease by transformer
What are the three causes of the opposition to current flow in an AC circuit?
Resistance, inductive reactance, and capacitive reactance
Define inductance
An induced voltage, which is opposite in direction to the applied voltage
Define impedance
Total opposition to the flow of current in an electrical circuit
Describe a basic OR gate
A standard logic symbol that has two or more inputs, and one output only one of the two input signals must be received (true) in order for there to be an output, signal transmitted
What is the standard unit of measurement for frequency?
Hertz
Describe a basic AND gate
Standard logic symbol that has two more inputs, and one output the two input signals must be received true in order for them to be an output, signal, transmit it
What is the basic unit of measurement for capacitance?
Farad
What is the common name for the lines of force that make up a field surrounding a magnet?
Magnetic flux, or flex lines
What does the acronym LED stand for
Light emitting diode
What is one of the most frequent causes of damage to solid state components, and integrated circuits
Electrostatic discharge (ESD) from the human body due to careless handling
What is the acronym ESD stand for
Electrostatic discharge
Why is a Hydro meter not used to measure the state of charge of a nickel cadmium battery?
It’s specific gravity does not change appreciably. The electrolyte of a nickel cadmium battery does not enter into the chemical changes that occur when the battery is charged or discharged
What is meant by electromagnetic induction
The transfer of electrical energy from one conductor to another that are not electrically connected
How high should the electrolyte level be in a properly serviced lead acid battery
Fully covering the plates, but only up to the level of the indicator in the cell
What is the basic unit of measurement for voltage?
The volt
What is the basic unit of measurement for current?
Amp
What is the basic unit of measurement for resistance?
Ohm
How can you identify a basic resistor?
By the color bands on it
Name at least two types of resistors
Fixed, variable, rheostat, potentiometer, thermistor
What are three things must all electrical circuits contain
Source of electrical energy, a load, to use the energy, and conductors to join the source and the load
What component creates capacitance in AC circuit?
Capacitor
How does a capacitor, store electricity?
electrostatic charge
What property of an AC circuit is defined by the term impedance
The total opposition to current flow
What are two reasons that might cause a nickel cadmium battery to fail to deliver it’s rated capacity
Faulty cells or cell imbalance
What electrical values are measured by typical multimeter
Voltage, current, resistance
When using a multimeter what setting or type a check is typically used to determine an open in a conductor
Continuity
