3.5 DC Sources of Electricity Flashcards
In a zinc carbon dry cell what is used as the electrolyte?
Water and Sulfuric Acid
In a zinc carbon dry cell what is used as the negative terminal?
Zinc (Zn)
In cells what is the purpose of the electrolyte?
Provides a path for electron flow, it also acts on the electrodes to cause a reaction
In cells what types of fluids can be used as electrolytes?
Salt, Acid or Alkaline solution
What are the 2 categories of cells and what is the difference between them?
Primary and Secondary, Once the primary is discharged it can not longer be used, Secondary cells are rechargeable.
What category of cell is a zinc carbon cell?
Primary Cell
What category of cell is a lead acid cell?
Secondary Cell
What category of cell is nickel cadmium cell?
Secondary Cell
What is done to the electrolyte to make a dry cell?
It is not in a liquid state but turned into a moist paste
What is the relationship between cell plate area and internal resistance?
The larger the plates and closer the plates are the more lower the internal resistance is and greater current transfer.
What is the relationship between cell plate distance and internal resistance?
The closer they are the lower the resistance is, the further they are the more resistance there is.
If a lead acid cell has 8 positive plates how many negative plates are required?
There is always one more negative than positive = 9 Negative plates
What is the function of a separator in a lead acid cell?
Hold the plates apart while allowing free movement of the electrolyte.
What is used to measure the specific gravity of a cell electrolyte?
Hydrometer or a refractometer
When is the electrolyte of a lead acid cell topped up?
Falls below the plates upper level.
What is the SG of a fully charged lead acid cell?
1.270 or “twelve seventy”
What is the SG of a full discharged lead acid cell?
1.835
What is the positive plate of a lead acid cell made of when fully charged?
Lead peroxide
What is the surface of a positive plate in a lead acid cell made of when discharged?
Lead Sulfate
What is the negative plate of a lead acid cell made of when charged?
Spongy Lead (pb)
What is the surface of the negative plate of a lead acid cell made of when discharged?
Sulfate ions combine with the lead in the plates and form lead sulfate on the negative plate.
What is the voltage of a fully charged lead acid cell?
2V per lead acid cell?
What is the nominal open circuit cell voltage of a Nicad?
1.3V
What is the SG of a fully charged Nickel cadmium cell?
1.300
What is the positive plate of a Nickel cadmium cell made of when charged?
Nickel Oxides
What is the surface of the positive plate of a Nickel Cad Cell when Discharged?
Nickel Hydroxide
What is the negative plate of a Nickel Cad Cell made of when charged?
Metallic Cadmium
What is the surface of a negative plate of a Nickel Cad Cell made of when discharged?
Cadmium Hydroxide
When should the electrolyte of a Nickel Cadmium cell be topped up?
When the electrolyte falls below the plates
What is the memory effect in a Nickel Cadmium Cell
Where the battery is not fully discharged before recharging limiting the amount of recharge and slow shortening the life of the battery.
What is required to generate electricity from a thermocouple?
Heat and 2 Dissimilar metals.
What is the maximum temperature for a Alumel Chromel Thermo Couple? What type is it?
1200 C (K Type)
What is the maximum temperature for a Iron-Constantan Couple? What type is it?
850 C (J Type)
What is the maximum temperature for a Copper Constantan Couple? What type is it?
400 C ( T Type )
Which parameter increases with an increase in temperature of a thermocouple?
Potential Difference (Voltage)
What are the 3 types of thermocouples used in aircraft?
T,J,K
What type of material are photovoltaic cell panels made of?
Semiconducting Materials
