DC Sources Of Electricity Flashcards
What is direct current
Current that flows through a circuit in one direction only
What is a cell used for
To store and supply electrical energy
When a primary cell is producing electrical energy what is being used up
The chemicals
When the cell is fingered to an external circuit electrons leave the zinc and flow via the?
Circuit to the carbon
When the chlorine ions leave the electrolyte positive ammonium ions remain and then move towards the?
Carbon rod
Alkaline cells are more expensive than the carbon zinc type but offer?
A longer life
Potassium hydroxide has a lower ____ than ammonium chloride
Resistance
The _____ cell is another type of alkaline cell and is used where the need for high capacity and small size outweighs its higher cost
Mercury
What batteries are more commonly used nowadays due to a higher energy content and better performance at extreme temperature
Lithium batteries
In a secondary cell the chemical changes which take place during discharge can be?
Reversed
A battery consists of what?
Several cells mounted in a container and provided with suitable electrical connections for series/parallel combinations for the cell
In cells an electrolyte does what resulting in external connections being made
Separated two charge collecting materials called electrodes
The size of a cell has no bearing on the ___ that it will produce, the generated ___ being determined solely by the materials used in its construction
Emf
The terminal voltage depends on the
Internal resistance of the cell
Size of the discharge current
charge state of the cell
The amount of electrical energy that a cell can provide form a new to the end of its useful voltage on load is called the cell capacity and is quoted in
Ampere-hours (AH)
Cells may be connected in what?
Series and parallel
When connected by series the battery
Voltage is the goal of the individual cell voltages
Battery resistance is equal to the total of the individual cell resistances
Battery capacity is the same as the capacity of a single cell
When connected in parallel
The battery voltage is the same as the voltage of a single cell
The battery resistance is equal to the parallel total of the cell resistances
The battery capacity is equal to the total of the individual cell capacities
Lead acid batteries typically have a normal voltage of
2 volts
In the conventional battery the plates consist of ____ grids into which the active materials are pressed.
Lead
Cells are generally constructed with an additional negative plate making both outside plates _____
Negative
The positive plates in areas acid battery are _____ peroxide (Pb02) , with the negative plates lead (Pb)
Lead
When the lead acid battery is delivering current, the sulphuric acid breaks up into hydrogen ions carrying a positive charge and _____ ions carrying. A negative charge
Sulphate
