Unit 13: Batteries and Other Sources of Electricity Flashcards
What is a voltaic cell?
A voltaic cell converts chemical energy into electrical energy. They are constructed from almost any two unlike metals and an electrolyte of acid, alkali, or salt. Voltaic cells depend on the movement of ions in solution to produce electricity.
What factors determine the amount of voltage produced by a cell?
The amount of voltage produced by a cell is determined by the materials from which it is made.
What determines the amount of current a cell can provide?
The amount of current a cell can provide is determined by the area of the cell plates.
What is a battery?
A battery is a group of cells connected together.
What is a primary cell?
A primary cell is a cell that cannot be recharged.
What is a secondary cell?
The secondary cell is characterized by the fact that once its stored energy has been depleted, it can be recharged.
What material is used as the positive electrode in a zinc-mercury cell?
Mercuric Oxide
What is another name for the Leclanché cell?
Carbon-Zinc Cell
What is used as the electrolyte in a carbon-zinc cell?
A mixture of ammonium chloride, manganese dioxide, and granulated carbon.
What is the advantage of the alkaline cell as compared with the carbon-zinc cell?
The average alkaline cell can supply from three to five times the energy of a carbon-zinc cell, depending on the discharge rate when the cell is being used.
What material is used as the positive electrode in an alkaline cell?
Manganese Dioxide
How is the A-hr capacity of a lead-acid battery determined?
The ampere-hour rating for lead-acid batteries is determined by measuring the battery’s ability to produce current for a 20-hour period at 80F. A battery with the ability to produce a current of 4 amperes for 20 hours would have a rating of 80 ampere-hours.
What device is used to test the specific gravity of a cell?
A hydrometer is a device for measuring the specific gravity of the electrolyte.
A 6-V lead-acid battery has an A-hr rating of 180 A-hr. The battery is to be load tested. What should be the test current, and what are the maximum permissible amount and duration of the voltage drop?
The test current will be 540 amperes (180 A x 3), and the voltage should not drop below 4.8 volts (6 V x 0.80) for a period of three minutes.
Three 12-V, 100-A-hr batteries are connected in series. What are the output voltage and A-hr capacity of this connection?
36-V output with 100-A-hr capacity.
What is the voltage produced by a silicon solar cell?
Silicon solar cells produce an open-circuit voltage of 0.5 volts per cell in direct sunlight.
What determines the current capacity of a solar cell?
The amount of current produced by a solar cell is determined by the surface area.
A solar cell can produce a voltage of 0.5 V and has a current capacity of 0.1 A. How many cells should be connected in series and parallel to produce an output of 6V at 0.3A?
12 cells should be ran in series to produce the desired voltage and that would need to be repeated to create 3 groups of 12 cells to be ran in parallel in order to produce the desired ampere output. 36 solar cells in total would be required.
What determines the amount of voltage produced by a thermocouple?
The amount of voltage produced by a thermocouple is determined by the type of materials used and the temperature difference between the ends of the junction.
A thermocouple is to be used to measure a temperature of 2800F. Which type or types of thermocouples can be used to measure this temperature?
Types R, S, & B.
What materials are used in the construction of a type J thermocouple?
Iron & Constantan
What does the word piezo mean?
The word piezo, pronounced “pee-ay-zo,” is derived from the Greek word for pressure. Piezoelectricity is produced by some materials when they are placed under pressure.
Three 12-V, 100-A-hr batteries are connected in parallel. What are the output voltage and A-hr capacity of this connection?
12-V output and 300-A-hr capacity.
