A
A utility-connected PV system is the most common system common system configuration.
True or False
True
A utility-connected PV system, also called a grid-tied solar system, is connected to the local electrical utility.
During the day, solar panels generate electricity that can power the home or business. When the solar panels aren't producing enough electricity, the building can receive additional power from the utility.
Depending on the utility's policies, excess solar energy may also be sent back to the electrical grid.
Think of a house with solar panels. During the day, the panels help power the house. At night, when the panels aren't producing electricity, the house uses electricity from the power company.
Solar irradiation equals the total solar irradiance received over time.
True or False
True
Solar irradiation is the total amount of solar energy received on a surface over a period of time.
There is a difference between two important terms:
Solar irradiance: The amount of solar power hitting a surface at a particular moment, measured in watts per square meter (W/m²).
Solar irradiation: The total solar energy received over time, commonly measured in kilowatt-hours per square meter (kWh/m²).
Think of a faucet filling a bucket. Irradiance is how fast the water is flowing, while irradiation is how much water has collected in the bucket over time.
This animated Disney Channel show follows a teenage girl and her family.
The Proud Family
In a series circuit, all components are connected end-to-end.
True or False
In a series circuit, electrical components are connected one after another, creating only one path for current to flow.
Current flows through every component.
The same current passes through each component.
If one component opens the circuit, current stops flowing through the entire circuit.
Imagine three light bulbs connected in series. If one bulb burns out and creates an open circuit, all three bulbs go out.
A battery ______ is a group of batteries connected together to provide specific voltage and capacity.
- Bank
- Garage
- Back-up
- Up-tick
Bank
A battery bank is a group of batteries connected together to store electrical energy and provide a specific voltage and capacity.
Batteries can be connected in two ways:
Series: Increases voltage while keeping the amp-hour capacity the same.
Parallel: Increases amp-hour capacity while keeping the voltage the same.
If you connect two 12-volt, 100-amp-hour batteries in series, you create a 24-volt, 100-amp-hour battery bank. If you connect them in parallel, you create a 12-volt, 200-amp-hour battery bank.
This successful businessman owned a chain of dry-cleaning stores and moved his family to a deluxe apartment in the sky.
George Jefferson
This teenager moved from West Philadelphia to live with his wealthy aunt and uncle in Bel-Air.
Will Smith
A mass spectrometer measures total global solar irradiance from the whole sky.
True or False
False
A mass spectrometer is used to identify and measure particles based on their mass-to-charge ratio. It does not measure solar irradiance.
The instrument commonly used to measure global solar irradiance is called a pyranometer.
A pyranometer measures how much sunlight is reaching an area, including sunlight coming directly from the sun and sunlight scattered through the sky.
Lockout and Tagout is not a needed precaution when dealing with photovoltaic systems.
True or False
False
Lockout/Tagout (LOTO) is an important electrical safety procedure used to prevent equipment from being unexpectedly energized while someone is working on it.
Lockout: Physically securing an energy-isolating device to prevent accidental operation.
Tagout: Placing a warning tag on equipment to notify others that it must not be operated.
Important: Solar panels can continue producing DC voltage whenever exposed to sufficient light, even when the inverter or disconnect is turned off. LOTO alone does not make every PV conductor safe.
If an electrician is servicing a solar inverter, they must follow the manufacturer's shutdown and isolation procedures, apply required LOTO controls, and verify the absence of hazardous voltage using appropriate testing procedures.
This is the last name of the family featuring Dre, Rainbow, and their children.
Johnson
Inverters convert DC power from batteries or arrays into AC power to serve local loads or for export to the utility grid.
True or False
True
An inverter is an electrical device that converts direct current (DC) into alternating current (AC).
Solar panels and batteries supply DC electricity, but most household electrical equipment operates using AC electricity.
An inverter allows solar-generated electricity to power household appliances, lighting, and other electrical loads. A properly designed grid-connected inverter can also export excess energy to the utility grid when permitted.
Solar panels produce DC electricity, but your home's receptacles typically supply 120-volt AC electricity. The inverter converts the solar electricity into AC power that your home can use.
The wafers in PV cells are made out of ____________.
- Titanium
- Lead
- Steel mix
- Silicon
Silicon
Silicon is the most common semiconductor material used to manufacture photovoltaic solar cells.
A silicon wafer is a thin slice of specially processed silicon used to create a solar cell.
When sunlight strikes the solar cell, it creates electrical charge carriers that can be collected to produce electricity.
Think of silicon as the main working material inside most solar panels. When sunlight reaches the silicon cells, they convert some of that light energy into electrical energy.
The first practical photovoltaic cell wasn't invented till the late 1990's.
True or False
False
The first practical silicon photovoltaic cell was developed in 1954 at Bell Laboratories.
Scientists discovered how to convert sunlight directly into usable electricity using silicon solar cells.
The photovoltaic effect itself was discovered much earlier, in 1839, by Edmond Becquerel.
Solar technology isn't new. Practical solar cells existed decades before the 1990s and were used to power satellites beginning in the 1950s.
This was the last name of the family headed by Cliff and Clair.
Huxtable
How do you measure roof slope?
- just read it with your eye
- Protractor
- Depth Meter
- Angle Finder
Angle Finder
An angle finder is a tool used to measure the angle or incline of a surface.
When installing solar panels, electricians need to know the roof's slope to properly plan the mounting system and panel orientation.
Roof slope can be described in degrees or as roof pitch.
For example, a 6/12 roof pitch means the roof rises 6 inches vertically for every 12 inches horizontally.
That equals approximately 26.6°.
If you're installing solar panels on a house, you can place an appropriate angle finder against the roof surface to measure its angle rather than guessing by looking at it.
In a parallel circuit, all voltage remains the same at each component.
True or False
True
In a parallel circuit, components are connected across the same two electrical points, creating multiple paths for current to flow.
Voltage is the same across every parallel branch.
Current can be different in each branch.
If one branch opens, the other branches can continue operating.
Imagine three light bulbs connected in parallel to a 12-volt battery. Each bulb receives the full 12 volts.
These twin sisters were separated at birth and reunited as teenagers.
Tia and Tamera
Increasing cell temperature decreases voltage, slightly increases current, and results in a net decrease in power.
True or False
When solar cells become hotter, their electrical performance changes.
Voltage decreases: Higher temperatures cause the panel's operating voltage to drop.
Current increases slightly: The panel may produce a small increase in current.
Overall power decreases: The voltage loss is generally greater than the benefit of the small current increase.
Remember the electrical power formula:
P = V x I
This nerdy neighbor was famous for his oversized glasses, suspenders, and the phrase "Did I do that?"
Steve Urkel
Standard time organizes regions into time zones, where every location in a time zone shares the same clock time.
True or False
True
Dallas and Houston are both in the Central Time Zone, so their clocks show the same time. New York is in the Eastern Time Zone, which is one hour ahead of Central Time.
Time-zone boundaries are determined by governments and don't always follow exact 15-degree divisions. Daylight saving time can also change the clock offset.
This comedian created a sitcom based on his childhood growing up in Brooklyn.
Chris Rock
In a series circuit, the current can vary from one point to another.
True or False
In a series circuit, current remains the same at every point because electricity has only one path to follow.
For example, if 2 amps flow through the first bulb, then 2 amps also flow through the second and third bulbs.
However, voltage is divided among the components.
Think of water flowing through a single pipe with no branches. The same amount of water must flow through each section of the pipe.
These two real-life brothers starred in a sitcom about siblings living in New York City.
Shawn and Marlon Wayans
All PV materials and technologies produce about the same efficiencies.
True or False
False
Not all photovoltaic (PV) materials and technologies have the same efficiency.
Solar panel efficiency measures how much sunlight a panel converts into usable electrical energy.
Different materials and manufacturing technologies produce different efficiencies.
For example:
Monocrystalline silicon: Commonly around 20–23% efficient in modern commercial panels.
Polycrystalline silicon: Often around 15–18% efficient in older commercial panels.
Thin-film solar panels: Efficiency varies by material and technology, often around 10–20%.
Imagine two solar panels that are exactly the same size. One has an efficiency of 15%, and the other has an efficiency of 22%. Under the same sunlight conditions, the 22% efficient panel produces more electricity.
What is the most common type of photoconductive cells used?
- Tin
- Gold
- Selenium
- Iron
Selenium
Selenium is a semiconductor material that changes its electrical conductivity when exposed to light.
This property makes selenium useful in certain light-sensitive devices, such as photocells and light meters.
Think about an automatic light that turns on when it gets dark. A light-sensitive device detects the change in brightness and signals the lighting system.
This character was famous for shouting "Dyn-O-Mite!"
J.J. Evans
Common personal protective equipment (PPE) for preparing and installing PV systems includes head, eye, foot, and fall protection.
True or False
True
Imagine installing solar panels on a two-story house. You need a hard hat, safety glasses, protective boots, and appropriate fall protection to reduce the risk of injury.
This comedian unexpectedly became responsible for raising his sister's three children.
Bernie Mac
The simplest type of PV system is the direct-coupled system, consisting of only an array and a DC load.
True or False
True
A direct-coupled PV system connects solar panels directly to a DC-powered electrical load without using batteries or an inverter.
The electrical load operates when the solar panels produce enough electricity.
Because the system has no battery storage, its operation depends on available sunlight.
Imagine a small DC water pump connected directly to a solar panel. When sunlight is strong enough, the panel powers the pump. When sunlight becomes too weak, the pump slows down or stops.
Direct-coupled systems must still have compatible voltage and current ratings and any necessary protective or control equipment.
This comedian played Michael Kyle, a father raising three children with his wife, Jay.
Damon Wayans