Basic Electronics Flashcards
What is the most important law applicable to study of electricity
Ohms law E =I X R
What are the elements of ohms law
Voltage E, current I, resistance R
What are the four sources of electrical energy
Thermal, light, pressure, and chemical
What does an electrical circuit consist of
A source (battery) ,a resistance or load (lightbulb) conductors (wires)
What represents capacitance in an AC circuit
A capacitor
What is the function of a capacitor
To store electricity
What is the unit of measure for capacitance
Farad
What is the standard unit of measure for frequency
Hertz
What is the basic component that only allows current to flow in one direction
A diode
What is inductance
When voltage is Inducted by magnetic Flux lines in a coil in an AC circuit. The inducted voltage is opposed in direction to the applied voltage and opposes any change in the alternating current
What is an example of an inductor in a magneto
The coil
What is impendance
The total Opposition for AC to flow caused by a combined affect of resistance inductive resistance and capacitive reactance in an AC circuit
What causes opposition to the flow of current in an AC circuit
Inductive, and capacitance reactants
What is the unit of measure for impedance
Ohms
What is the general purpose of a resistor
To limit current
How May the value of small, fixed resistor be determined
By the color band on the resistor
What are the two things that happen when current flows through conductor
A magnetic field is generated and a conductor heat up
What is the common name for the lines of force that make up the field surrounding the magnet
Magnetic flux lines
What is the concept that describes the relationship between electricity and magnetism
Electromagnetism
What are the four factors that affect the resistance in electrical current
The wire gauge length temperature and material
What is the unit of measurement of power in a DC circuit
The watt. Amperes Times voltage equals watch P= I x E. 746 whats equal 1 Horse power
What is a kilowatt
1000 W
In a DC circuit, what occurs when voltage is increased while the resistant remains constant
Increase in current
What are the three types of DC electrical currents
Siri circuit, parallel circuit, complex circuit
A 24 V lead acid battery has how many cells
It has 12 cells and each sale is rated at approximately 2 V
What are the units that the battery capacity is measured in
Ampere-hours
What should be the specific gravity of the electrolyte in a fully charged lead acid battery
It should be between 1.275 and 1.300
What instrument is used to determine the specific gravity of an electrolyte in a lead acid battery
A hydrometer
Why can’t a hydrometer not be used to determine the charge of a nickel cadmium battery
The electrolytes in a nickel cadmium battery does not change appreciable during charge or discharge of the battery
When using a hydrometer to check the charge of a lead acid battery, at what temperature must a correction factor be applied to the reading
Adjustments must be made if the temperature of the electrolyte is above 90 or below 70°F
What is electromagnetic Induction
Transfer of electrical energy by means of a magnetic field. Transferring voltage from one conductor to another without physically touching
How are battery compartment protected against corrosion
Coded with a special corrosion resistant paint such as bituminous paint
What should be the correct electrolyte levels in a properly service battery
3/8 inches above the plates
What are paralleling generators and how is the load distributed
If two or more generators are operated at the same time supply power for a load that must be shared equally
Describe a non-tripped circuit breaker
A trip free breaker makes it impossible to hold the circuit closed if it pops with the circuit gets hot you cannot be reset until it gets cold
Can you store a NiCad or lead acid battery together
No the fumes can contaminate the electrolyte in the NiCad battery from the lead acid battery
What is the result of an in balance to sell in a nickel cadmium battery
When his cell has low internal resistance, current will increase across the cell, causing the heat up
What happens to specific gravity of an electrolyte in a lead acid battery when the temperature changes
Reading on the hydrometer will vary with temperature variations
For example as the temperature of the electrolyte increases, the specific gravity reading will be high, and cold or electrolytes will have a lower apparent reading
What is an L.E.D.
Light emitting diode
What is a S.L.A.battery
Sealed lead acid battery
What is the basic unit of measure for inductance
Henry
What prevents reverse current flow in a D.C.alternator
Reverse current cut out
