Circuits, Electricity and Lights


Webelos and Bears

Teaching electrical technology and engineering skills to Webelos and Bears

cel-1

Introduction

This class will teach Webelos and Bear den leaders how to teach electrical and electronics technology to their scouts.  The information will be presented assuming the leader and the scouts have no familiarity with electricity or building a circuit, so even the newest leader can understand and teach the adventures.  Electrical and electronic components and devices make our modern world function.  In this class we will look at both the power side and electronic side of our electrical world.  Starting with a simple lighting circuit that you’d find in a typical home to an electronic breadboard that simulates how electronic components are placed and wired in circuit boards. Using symbols, drawings and schematics, and tool and material lists we’ll put together a few simple projects to learn how to teach circuits, electricity, and lights to our scouts.

Concept:

This class will break down how to present circuits and electricity by learning through doing.  Two different applications will be presented for the leader to choose from: electronic circuit board wiring and electrical wiring.  The electrical wiring consists of an outlet, a switch and a light like you would find in a typical home.  The electronic circuit board consists of a battery, a toggle switch, and a 12v lamp.  The low voltage option may be best for those who don’t feel comfortable working with 120v.  Both circuits present the same concept of a power source, a switching device, and a load, in this case a light.  

This class is broken down into three categories: theory, drawings and diagrams, and the practical project.  How you choose to present the different topics to your scouts is entirely up to you.  You may want to do the project only and not go over the science of the circuit or the drawings. It’s up to you.

Electricity in WEBELOS AND BEAR books

Both the Bear and Webelos books discuss electricity.

In the Bear manual (page 117) there is a section on electricity that discusses conservation efforts. The electrical project in this handout could help to show them the different energy conserving light bulbs.

In the Webelos manual (page 394) it discusses the different types of energy conserving light bulbs.  The electrical project in this handout could be a fun project to have them put in and discuss different types of light bulbs.

Part one: Theory

Optional Supplies for demonstrating the concept:

Ping-Pong Balls (pack of 6 – around $3)

Paper Towel Tube

Dowel or rod

Simple Definitions:

Electricity:  Electricity is a form of energy.  Atoms have charged particles called electrons, and when we make those electrons move, we get electricity.

Voltage:  The electrical force or push/pull on electrons.

Current:  The flow of electrical force on the electrons.

Resistance:  The opposition to current flow in a circuit.

Electrical Circuit:  A path for electrical energy to flow.

Battery:  A device that changes chemical energy into electrical energy.

Example:

One way to demonstrate this concept is by using ping-pong balls a paper towel tube and a dowel.  Fill the paper towel tube with the ping-pong balls and push them out with the dowel.  The ping-pong balls represent electrons and the push with the dowel represents the voltage or electrical force applied to make the electrons move.  The scouts could try this a few times pushing harder or softer to change the rate the ping-pong balls come out.  This would represent different voltage levels resulting in different current flows.

Part Two: Symbols & Diagrams

Figure 1
Figure 1
Figure 2
Figure 2

Part Three: Projects

Electronic Circuit

Using the electronic schematic in figure one and the electronics parts list, we will build the simple circuit to turn on our 12v lamp.

Getting to know the solderless breadboard.  The breadboard is laid out in a grid system with some rows and columns connected together electrically.  Depending on what style you have, the layout could vary. Knowing how the breadboard is constructed is a must.

Step 1:

Place the components in the breadboard.  Arrange the components so that the component leads are landed on different rows, and place the components far enough apart to wire them.

Step 2:

Wire the components together.  This will complete the electrical circuit.  Starting with the battery connector positive (+) lead, wire from the lead to one of the two leads on the toggle switch. Next place a wire from the other toggle lead to one of the lamp leads.  Finally, wire from the other lamp lead back to the battery connector negative (-) lead. This will complete the circuit.  

Step 3:

Turn it on, and test it out.  If you haven’t connected the battery yet, go ahead and hook it into to the battery connector snaps.  Now it’s time to turn it on, if it’s not already.  Flip the switch, and see if you’re a successful electronics technician.

Electrical Circuit

Using the electrical schematic in figure two and the electrical parts list we will build the simple circuit to turn on our 120v lights.  This circuit, while the same electrically, is a little more involved to put together and will need more time to complete.  If helpful, the outlet boxes and devices could be pre-mounted to the wooden backer board before the den meeting to give you more time to wire. 

Step 1:

Place the outlet, switch, and fixture boxes on the wooden backer board and screw them down.  Make sure to leave enough room, 12” – 18”, between devices to provide adequate wiring room.

Step 2:

With the power cord unplugged, run the cord with the exposed leads through the switch box clamping ring leaving about 3”-4” of leads into the box and tighten the clamping ring.

Step 3:

Cut the Romex (cable/wire).  Using cutting pliers, cut 2 pieces of Romex about 2 feet long, long enough to reach from the switch box to each of the other boxes with about 6 inches leftover in each box to make up the connections.

Step 4:

Wire the switch box.  

  1. Cut and strip back the Romex from the 2 pieces in the box to expose the white (neutral) and black (ungrounded or hot) conductors inside.  Strip the insulation from the wires about an inch.  
  2. Strip the cord and plug leads to the same length.  You should have 3 sets of black and white exposed conductors at this point.  
  3. Make a piece of black conductor about 4” long from a spare piece of Romex.  Wire one end of this conductor to either of the switch black screws.
  4. Tie the neutrals together.  Take all (3) white conductors and tie them together using a wire nut.
  5. Tie the bare grounds together.  From the same spare piece of Romex, take the piece of bare copper wire and wire it to the green ground screw on the switch.  Wire all (4) bare ground leads together with a wire nut.
  6. Wire the switch.  This step is very important: take the black lead from the plug cord, the black lead from the piece of Romex going to the outlet box, and the black lead from the switch and tie these (3) leads together using a wire nut.  The black lead going from the switch to the fixture box should be unconnected at this point.  Take the remaining black lead going to the fixture box and wire it to the other screw on the switch.
  7. Screw down the switch.  With all ends connected and no unconnected wires left in the switch box, carefully fold the wires back into the device box, and pushing on the switch yolk, press the switch into the box.  Using the screws that came with the switch screw down the light switch into the device box.
  8. Put on the switch cover.  Using the switch cover screws provided with the cover, put the cover on the switch.  This will make the make the switch and box assembly finger-safe so no electrified parts of the switch will be exposed.

Step 5:

  1. Wire the outlet box.  The outlet box should only have one piece of Romex going into the device box.  Make sure you have about 6” of conductors that come into the box to leave enough wire to work with.  Cut and strip back the Romex outer sheath to expose the black and white conductors inside.  Strip the conductors back an inch exposing the bare copper.  Wire the black conductor to the gold screw on the receptacle, the white conductor to the black screw, and the bare copper conductor to the green screw on the receptacle.  Some receptacles will have a convenient stab-in connection on the back that may make wiring the receptacle a lot easier.
  2. Screw down the receptacle to the box.  Once all the connections are made and there are no unconnected wires, carefully fold the conductors into the box and using the yolk on the device, press it into the box.  Using the screws that came with the receptacle, screw down the receptacle into the device box.
  3. Put on the receptacle cover.  Using the switch cover screws provided with the cover,  put the cover on the switch.  This will make the make the receptacle and box assembly finger-safe so no electrified parts of the receptacle will be exposed.

Step 6:

  1. Wire the fixture box.  The fixture box should only have one piece of Romex going into the device box.  Make sure you have about 6” of conductors that come into the box to leave enough wire to work with.  Cut and strip back the Romex outer sheath to expose the black and white conductors inside.  Strip the conductors back an inch exposing the bare copper.  Wire the black conductor to the gold screw on the fixture, the white conductor to the black screw, and the bare copper conductor to the green screw on the fixture.
  2. Screw down the fixture to the box.  Once all the connections are made and there are no unconnected wires, carefully fold the conductors into the box and using the ceramic ring on the fixture, press it into the box.  Using the screws that came with the fixture, screw down the fixture into the device box.  Once the fixture is on the box, it is finger-safe.

Step 7:

Screw in a light bulb and turn it on.  Make sure the switch is in the off position and plug in the circuit.  Flip the switch and see if you’re ready to rope houses with the best of wire monkeys.

 

Electronics Project Parts List
Line No Quantity Description Price ea Total
1 1 solderless breadboard and wiring kit 20.00 20.00
2 1 9v battery 6.00 6.00
3 1 9v battery connector 3.00 3.00
4 1 Toggle Switch, accepts leads 3.00 3.00
5 1 12v rated miniature lamp with leads 3.00 3.00
Total: $35

 

Electrical Project Parts List
Line No Quantity Description Price ea Total
1 1 3ft wide x 2ft tall 1/2″ piece of plywood $15.00 $15.00
2 1 Grounded power supply cord $5.00 $5.00
3 1 Round Electrical Box (fixture) $5.00 $5.00
4 2 Handy Boxes, Deep, Single Gang $1.00 $2.00
5 2 Handy box extension (*optional, if needed) $2.00 $4.00
6 1 Cable Clamp Connector package of 5 $2.00 $2.00
7 1 Switch, Single Pole, 15A rated $1.00 $1.00
8 1 Switch cover $1.00 $1.00
9 1 Duplex Receptacle, 15A rated $1.00 $1.00
10 1 Receptacle Cover $1.00 $1.00
11 1 Keyless lamp holder, plastic (light fixture) $2.00 $2.00
12 1 Romex, 15 foot roll $7.00 $7.00
13 1 Wood screws, Package of 101/2″ long for mounting devices $2.00 $2.00
Total: $48.00

 

Tools Needed
Line No. Tool Name Description For Project
1 Wire strippers 18 awg – 26 awg wire strippers (red) electronics
2 Wire Strippers 10 awg – 16 awg wire strippers (yellow) electrical
3 Flat Head Screwdriver Flat head Screwdriver electrical
4 Phillips Head Screwdriver Phillips Head Screwdriver electrical
5 Cutting Pliers Side cut or linesman type pliers electrical
6 Utility Knife Razor knife, box cutter electrical
7 Needle Nose Pliers Needle Nose Pliers electrical
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s