Solar Photovoltaics (PV) Installation Exam | Questions & Answers (Rated A+)
Solar Photovoltaics (PV) Installation Exam | Questions & Answers (Rated A+)
What is the definition of photovoltaics (PV)? - ANSWER - the science of turning sunlight directly into electricity
What does the abbreviatio...
Solar Photovoltaics (PV) Installation
Exam | Questions & Answers (Rated A+)
What is the definition of photovoltaics (PV)? - ANSWER - the science of turning sunlight
directly into electricity
What does the abbreviation "PV" stand for? - ANSWER - Photons of light and Volts of electricity (photovoltaic)
What do PV modules consist of? What are these typically made of? - ANSWER - solar cells; silicon
What is silicon? - ANSWER - a semiconductor material made from sand
What happens when photons enter a solar cell? - ANSWER - the photons excite the electrons in the silicon layers, causing movement and a continuous flow of energy through a circuit of wiring that feeds into the PV system
What is direct current (DC)? - ANSWER - current where all electrons are moving in the same direction (produced by all PV modules and used by all batteries)
What is alternating current (AC)? - ANSWER - current where the electrons move back and forth (changing direction about 60 times per seccond)
In your home, what uses AC? - ANSWER - electric systems and most appliances
PV systems use both DC and AC to get the job done. What does this concur? - ANSWER - PV systems include one or more inverters that convert DC solar-generated electricity to usable AC power
Other than converting DC to AC, what is the purpose of inverters in grid-tied systems? - ANSWER - selling power back to the utility grid
In a PV system, what purpose does an inverter serve? - ANSWER - converting DC to AC
What materials do the layers of a PV module consist of, bottom to top? What frames it? - ANSWER - Backing material, crystalline silicon cells, a bonding sheet, and tempered glass; metal frame (commonly aluminum)
What does a single solar cell consist of? - ANSWER - silicon layers separated by metal conductors
What is the typical size of a solar cell? - ANSWER - 4" or 6" square How many interconnected solar cells does a full-sized PV module contain? - ANSWER -
60 or 72
What is crystalline silicon (c-Si)? What is it capable of producing? - ANSWER - a semiconductor material; 0.5 volts of electricity
What is another word for current? - ANSWER - amperage
In a solar cell, what does the amount of current (aka amperage) that is produced depend on? - ANSWER - the size of the cell
How many volts would 60 solar cells wired together typically produce? - ANSWER - 30 volts (60 cells x 0.5 volts = 30 volts)
How many volts would 72 solar cells wired together typically produce? - ANSWER - 36 volts (72 cells x 0.5 volts = 36 volts)
Why are solar cells assembled into PV modules (2 reasons)? - ANSWER - 1. it takes a lot of cells wired together to make a useful amount of electricity produced at a relatively high voltage
2. crystalline silicon cells are fragile. The structure and glass top protect the cells from the elements (but they CAN break if you drop them the wrong way)
Approximately how long can PV modules withstand outdoor elements? - ANSWER - several decades
What is a PV array? - ANSWER - a collection of solar-electric modules
Where can PV modules be installed? - ANSWER - on the roof or on the ground
What is a collection of PV modules wired together in a group called? - ANSWER - PV array
What is a series-string? - ANSWER - each group of PV modules wired together
Where are series-strings joined together? - ANSWER - at a combiner box near the array, which carries power to the rest of the system's components at ground level through supply lines (wiring)
What determines the first component that the combiner box's supply lines connect to? - ANSWER - the type of PV system
What are the 3 types of PV systems? - ANSWER - grid-tied, off-grid, and grid-tied with battery backup
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