electrical circuits featuring snap circuits getting started with electricity – level 1

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Electrical Circuits featuring Snap CircuitsGetting Started with Electricity – Level 1





What You’ll Learn… What electricity is and how to control it The four basic elements of a circuit The difference between AC and DC current What transformers are and how they are used Safety tips for working with electricity How to identify and avoid dangerous short circuits Proper care of fragile and delicate electrical equipment How to design simple circuits using Snap Circuits How electrochemical batteries work How to build and use a continuity test circuit





Rewrite and answer the following questions in your Word Document. Ensure you save this document to your group’s file.

1. Define electricity.2. What is Lightning?3. What are the atoms that are positively and negatively charged called?4.What do AC and DC stand for? Why are they named these?5. Name the two types of electrical circuits?6. How many cycles per second does AC voltage alternate?7. What is a transformer used for?8. What is a conductor(in electricity)?9. What is an insulator?10. How many volts in household current?





What is electricity?

What You Should Know…Electricity is simply the flow of electrical power or charge. There are different forms of electricity. You’ve almost certainly experienced static electricity after walking on a carpet and touching a door knob. That shock you felt was a flow of charged particles from your finger to the door knob. Lightning is an extreme form of static electricity caused by the build up of charged particles in rapidly moving air currents.

As you probably know, atoms have positively charged particles called protons and negatively charged particles called electrons. Both carry an electrical charge. It’s relatively easy to dislodge electrons from the outer orbit of an atom in certain substances like copper wire. Such substances are called conductors. When that happens, the atom’s charge is out of balance and it attracts another electron. This flow of electrons is the electricity we use to power our homes and appliances.





What You Should Know…Electrical energy flows in wires like water in pipes…

Similar to a stream of water though a hose, electricity is a stream of electrons flowing in a conductive wire. It flows when electrical pressure is applied to the wire. We call that electrical pressure voltage.

The resistance in this heater consumes electrical energy as it converts the

electricity to heat and light.

Nozzle(Resistance)

Smaller Pipe(Resistance)

Flow Control Valve

Gravity Pressure

(force)

The flow of electrons starts with a generator and travels

through wires to the point where it is consumed

Flow Volume in Gallons per Minute





Basic Two Types of Circuits:

Parallel and Series All circuits, whether they be electrical, pneumatic, hydraulic or the plumbing pipes in your home water system have these FOUR things in COMMON…

1 2

3 4

Energy Source Path

LoadFlow Control

Devices

They all have an energy source, a path that the energy follows, flow control devices, and a load that consumes the energy.

Wires Tubing

Lights CylindersSwitches Valves

Outlets Batteries

Air Compressor

What You Should Know…





Evolution of AC and DC electrical currents…


There are two types of electrical currents – AC (Alternating Current) and DC (Direct Current).

Thomas Edison was a supporter of DC current, so he built DC power stations in many major cities in the late 1800’s. But DC power had one major limitation – power plants could only send DC electricity about one mile before the electricity began to lose power.

In 1896, George Westinghouse introduced a high-voltage alternating current (AC) transmission line from his Niagara Falls hydroelectric plant to Buffalo New York, 20 miles away. This project established the common practice of locating electric generating plants long distances from the end consumer.

Study the two animations on this page carefully to see the difference in the direction the current is flowing in the top DC circuit and the bottom AC circuit.

Source: PBS Online – AC/DC: What's the Difference?

DC Circuit

AC Circuit

DC current flows in one continuous direction.

AC current alternates

its direction 60 times

every second.

All your experimental

circuits will use DC current.





+-

Understanding AC – Alternating Current…


AC stands for alternating current because it alternates its polarity from positive to negative at a rate of 60 cycles per second in the USA, which can be visualized as a sine wave. The electricity coming out of the wall outlets in your home is AC.

AC Generator

AC generators are like electric motors in reverse - they

produce electricity instead of use it!

Sine Wave





Power Adaptors transform

electrical energy


DC stands for direct current because it only flows in one direction. DC current from solar photovoltaic panels and wind turbines can be stored in batteries for later use.

Electrochemical batteries are manufactured with the ability to provide DC power that is chemically produced inside the battery cells.

Power adapters on electronic devices like computers, camcorders and many other devices in your SmartLab convert AC power from the wall socket into DC power for the device.

Understanding DC – Direct Current…

Direct Current





Batteries

What You Should Know…The benefits of DC – Direct Current…

Portability!

How many battery powered devices do you have with you right now?

They are all using DC power!





The battle of the currents continues today…


While the vast majority of our bulk electricity is still being transmitted and delivered as AC current, modern technologies have enabled DC current to make somewhat of a comeback in the world.

Do an online search for “High-voltage Direct Current” (HVDC) and you will find that high-voltage DC electric power transmission systems are being built today.

At the time of Thomas Edison, DC power could not be economically transmitted long distances. But now some experts are saying that long-distance HVDC systems are less expensive and suffer lower electrical losses. The technology that makes HVDC transmission possible was developed in Sweden in the 1930s.

The longest HVDC link in the world is currently a 600 MW link 1,100 miles long called the Inga-Shaba in the Democratic Republic of Congo.

1000 KV HVDC Transmission Lines in US

1100 mile HVDC Transmission Line, Congo

Edison Westinghouse

Vs.





Transmitting electrical power over long distances, like from large electrical power stations to your home, requires very high voltages. Most of these high-voltage transmission lines carry between 138,000 to 765,000 volts. Very dangerous!!!

Transformers are used to reduced the voltage before it enters homes and businesses.

What You Should Know…Transformers can change the voltage…

Electrical transformers change the voltage





The ability to change and transform electrical energy is one of the characteristics that makes electricity such a popular form of energy.

The induction coil in cars raises the 12 volts coming from the battery to the 15,000-20,000 volts needed to produce a good ignition spark in the spark plugs.

What You Should Know…Transformers can change the voltage…

12 Volt Battery

IgnitionCoil

SparkPlug





Many electronic devices need a lower voltage than you get from a 120 volt AC wall socket, and sometimes they also need DC current instead of AC. That’s why you see a lot of small transformers called power adapters in your SmartLab and at home.

Your SmartLab electricity kit can be powered by AA batteries or by connecting a power adapter that transforms 120 volts AC into 5 volts DC.

What You Should Know…Transformers can change current too…

120 volts AC Input

12 volts DC Output

A power adapter is a transformer.





Safety first…Be sure you read these safety points!Fortunately, none of the electronic components in your Tronix kit carry enough power to be dangerous. But that might not always be the case with electrical circuits you might encounter elsewhere.

So when you are working with electricity, it’s always a good idea to develop safe work habits.

Caution!

NEVER touch loose wires unless you are SURE they are disconnected from a power source.

ALWAYS make sure that power is switched OFF when making changes to an electrical circuit.

If in doubt, ask for HELP from a knowledgeable responsible person. Better safe than sorry!





Some things you will work with in the SmartLab are STRONG and TOUGH. But electronic equipment is fragile and delicate by nature, because the wires are very small and easy to break.

So how should you treat them?

Electronic components are fragile, handle them with care!

Proper care of delicate electronic equipment…

Caution!





How to avoid a short in your circuit…

Red wires should NOT

be there because they cause a short

circuit.

Short Circuit – a “short” in a circuit occurs when an alternate path (with less resistance) to the intended path is introduced. A path with no resistance allows too much current to flow. If the location of the short in a circuit only partially reduces resistance, it’s called a minor short. Minor shorts will typically disable a component in your circuit. If the location of a short eliminates all resistance, that’s called a dead short. Circuits with a dead short quickly melt or burn something up!

The electrical opposite of a short circuit is an "open circuit", which happens when a wire is broken or missing so that no current can flow. Open circuits cannot operate but they do not damage anything like a short circuit does.

Caution!

Shorts usually occur when

someone puts an extra wire in the circuit.

Dead ShortMinor Short

A minor short just disables one component, but a dead short burns something up!





The GREEN circle indicates DC power

The BLUE circle indicates AC power

Set the MultiMeter on 20 DCThe RED circle

How to set up the MultiMeter





Here’s What You Do-Check out the Voltage Kit from Mr. Ochs1. Identify the following parts on the digital multi-meter AC voltage, DC voltage, resistance, continuity, DC amperage, and AC amperage.2. Learn to measure and compare the voltages of the various batteries in your collection. Make a simple chart or table in WORD to record your findings. List the advertised voltage in the second column of your data chart and the actual measured voltage in the third column.a. Make sure the DMM is set to measure DC voltage.b. Touch the red lead to the positive end of the battery and the black lead to the negative end of the battery. What voltage do you get? Write it in your chart.c. Repeat this process with each of your batteries until you have tested them all, and be sure to write your test results in your data chart.

BatteryTo be tested

Advertised Voltage

Measured Voltage

First Activity, test batteries…





Next with EDISONLook for the software in Quick Access…





Start with EDISONCreate a circuit for each of the schematics on the right…Take a picture and Label them.

Battery

Light

Push Switch

Series Circuit





Start with EDISONCreate a circuit for each schematic on the right…Label them

Parallel Circuit





Stuff You’ll Need …This is some of the Snap Circuits basic electricity collection you’ll need…





You must make sure you insert the AA batteries correctly or it will melt the battery case and ruin it. The negative end goes against the spring.

How to properly install your AA batteries…

Caution!

Opposite ends?

Like this…

Your batteries should face opposite directions like these.

Batteries should never get warm!





You’re ready to get started making actual circuits, but before you can start you need a clear board and the snaps.

What’s a schematic…?

Do It!

Schematic – A schematic is a simplified graphic representation of a circuit using lines and symbols rather than actual pictures of the electrical components and wires. You should learn to read the schematic drawings like the ones above, and you should learn to sketch simple schematics of your own circuits.

Lights

Battery

Switch

Lights

Bat

tery

Switch

Build your circuits on the clear board with the little holes even though we do not show the clear board in many of the slides that follow.





Use these parts to create your first simple circuit using the schematic drawing below. Then wire the previous circuits with up to three bulbs, in series and parallel, document.

This circuit has only one path for the electricity to follow.

Push-Button Switch

Lamp Holder

Simple electrical Series and Parallel circuits…

Do It!

Put these components on the clear board and use the snaps to connect the battery (-) to the switch,

the switch to the light, and the light to the battery (+).

Battery

Light

Push Switch





Your first circuit was pretty easy wasn’t it.

So what kind of switch is a push-button switch? Does the light stay on when you let go of the button? Can you think of any switches in your house that work like this?

This type of switch is called a momentary switch. It’s only on for the moment that you are pressing the button. Your doorbell works like that, right?

Simple electrical circuits…

Do It!Push-Button

Switch





How electrochemical batteries work…

Do It!

Why does electricity follow the path of wires? Why doesn’t it just go wherever it wants or why doesn’t it just sit there and do nothing?

What makes electricity move at all?

Earlier you learned that electricity is the energy produced by the FLOW of ELECTRONS. So what makes the electrons start flowing?

Well, the answer is PRESSURE. We call this pressure VOLTAGE. In the case of batteries, this pressure or voltage is created because of a chemical imbalance that exists in the battery.

Let’s discuss a simple analogy to help you understand how a battery works, which will also help you answer the other questions above.

A battery has a positive side and a negative side. The inside of a battery is made up of layers of special materials and chemicals.

The materials connected to the negative side of the battery have surplus electrons that they want to get rid of.

The materials connected to the positive side are electron deficient, so they are wanting to get more electrons.

Surplus Electrons

Needs Electrons

How can we get these two sides of the battery

together?





Do It!

Why can’t the surplus electrons from the negative side get over to the positive side?

They can’t get there because they need a conductive path. The air gap between the negative pole and the positive pole is preventing them from crossing over. They need a path made of a material that conducts electricity.

Some materials conduct electricity (conductors) and others resist the flow of electricity (insulators). Your challenge is to find out which types of material are good conductors and which are insulators. You can build a simple test circuit as shown here and on the next slide to test the conductivity of a variety of different materials.

Conductors versus Insulators…

Test Materials

Light





Item Conductor or Insulator

1. Rock

2. Graphite

3. Copper (Penny)

4. Spoon

5. Paper

6. Wood

7. Paper Clip

8. Other

Do It!

Electricians usually use a digital multimeter to test the conductivity (the ability to conduct electricity) of wires that might be damaged.

But you are building your own conductivity tester as you see here. Touch the loose wires to each of the materials you are testing. If the light comes ON, the test material is a conductor. If the light stays OFF, the material is an insulator.

Building a continuity tester…

Which of these materials will conduct electricity? You can use materials like those below or any other materials you can test.

Ask Mr. Ochs for these materials!





Do It!

Now that you know the types of materials that conduct electricity… you could provide a path for the electrons to flow from the negative side of the battery through a light to the positive side.

How electrochemical batteries work…Eventually though, the battery will be dead and the light will go out. How and why does that happen?

In the beginning there was an imbalance between the negative and positive sides of the battery, which created the potential for energy to flow. But now they are balanced, so the electrons quit flowing and you have no current. The voltage from your battery will gradually decrease until it is completely dead.

Voltage

Time

New Battery Dead Battery

electrical circuits featuring snap circuits getting started with electricity – level 1

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