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Shopping List

The easiest way to obtain parts for the nine experiments in this workshop is by ordering a kit. You can order your Easy Electronics kit and handbook bundle (including three additional experiments) from Maker Shed.

If you prefer to shop for parts individually online, I suggest sites such as ebay.com, mouser.com, digikey.com, or newark.com.

- copy:

Here’s a complete list of everything you need for the 9 experiments in this workshop.

Batteries

Alkaline AA size.

Quantity: 3.

Note: Do not use lithium batteries!

Battery Holder for Single AA Battery

With solder pins or PCB terminals. Eagle Plastic Devices part 12BH311P-GR or similar.

Quantity: 3

Battery Holder for Three AA Batteries

With solder pins or PCB terminals. Eagle Plastic Devices part 12BH331P-GR or similar.

Quantity: 2.

Miniature Incandescent Light Bulb

This item is sometimes sold as a “lamp”. The one that I prefer, pictured throughout this book, is rated for 5V and 60mA and has a ceramic base with two short leads. Search for JKL 7361 by JKL components, or CM7361 by Chicago Miniature Lighting, a subsidiary of VCC. If these options are unavailable, a very similar bulb is JKL 7362; it will use more current and will be a bit dim when used with a series resistor, but should work in the experiments. Another option is to use a 6V bulb rated for 40mA or 60mA; these usually have a size E10 screw-thread base, and require a matching socket. Search online for E10 6V bulb, and you will find scientific supply companies selling the bulb and socket for high-school electrical experiments. It may be less bright than an equivalent 5V bulb, but should work.

Quantity: 2.

Alligator Jumper Wire

Single wire with alligator clip at each end. Any length, but very short ones are more convenient (3" to 6").

Quantity: 2 red, 2 black, 3 green.

Slide Switch

Also known as a slider switch. To use it with alligator clips, it should be as large as possible, with pins widely spaced. This can be a problem, as most slide switches today are subminiature. I suggest that the minimum body size is 1/2" or 13mm long, minimum pin spacing 1/8" or 5mm. You want a single-pole, double-throw switch, which may be identified as SPDT, SP2T, 1P2T, or PDT. Examples of an acceptable switch are part number PM13B012 by Apem or L102011MS02Q by C&K Components. You will be switching very small currents at only 4.5V, so you do not need to be concerned about maximum voltage or amperage listed for a switch.

Quantity: 1.

Resistors, Quarter-watt, 5% or 10% Tolerance

You will need values 33 ohms, 1K, 10K, and 100K: 2 of each. Values 2.2K and 3.3K: 1 of each.

Transistor, 2N3904 NPN Bipolar

Purchase from any manufacturer.

Quantity: 2.

LED

Low-current type, tinted red. Avago or Broadcom HLMP-D150, or HLMP-D155, or HLMP K-150, or HLMP K-155, for a typical 1.6V forward voltage, 20mA maximum average current but able to respond to 1mA.

Quantity: 2.

Phototransistor

Lite-On LTR-301 preferred, side-facing NPN type, rated 5V. Alternatively Optek / TT Electronics OP550B. (The O at the beginning of this part number is letter O, the 0 near the end is numeral zero.) The component that you use must be able to pass a constant current of 3mA. If you find that a side-looking phototransistor has both leads of equal length, hold the component with the lens facing you and the leads pointing down, and the right-hand lead is probably the collector (more positive). If in doubt, apply power very briefly.

Quantity: 1.

Capacitors, Electrolytic

Rated 10V or higher. 1µF, 10µF, 100µF, and 470µF.

Quantity: 1 of each.

Capacitors, Ceramic

2.2nF, 10nF, and 100nF. (These values may be written as 0.0022µF, 0.01µF, and 0.1µF.)

Quantity: 1 of each.

7555 Timer Chip

Preferred manufacturer is Intersil. If you try using a 555 timer chip, it will consume more current and may not work well at the low voltage in the experiments in this book.

Quantity: 1.

Mini Breadboard

17 rows of holes or more.

Quantity: 1.

Jumper Wires

22-gauge, stripped at both ends, in colors red, green, and black.

Length of insulation 1/2": 3 of each color.

Length of insulation 1": 2 of each color.

Piezoelectric Audio Transducer

With wire leads, DB Unlimited TP244003-1 preferred. Alternatively, CPE-827 from CUI Inc. If you search online, note that piezo is often used as the abbreviation for piezoelectric, and you should search for “piezo speakers” to avoid finding other kinds of transducers, some of which work like microphones. If making a substitution, larger is better (minimum diameter 1" or 25mm).

Quantity: 1.

Optional Items

Laser Pen

Used for triggering phototransistor.

Quantity: 1.

Magnifying Lens

Useful for reading part numbers).

Quantity: 1.

Nail Clippers

Used for trimming unruly component leads.

Quantity: 1.

Wire Strippers

For if you’d rather make your own jumper wires.

Quantity: 1.

Credits + Acknowledgements

Workshop author image
Charles Platt Author

Charles Platt is a contributing editor to Make: magazine and author of the bestselling book Make: Electronics. Formerly he was a senior writer at Wired magazine.

Explore all of Charles’s books here at Platt Electronics.

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Hands-on learning for makers.


This workshop is adapted from the Easy Electronics handbook and kit — all available from Make:.

LESSON 1

Power and Light

Ever been curious about how power flows through a light bulb? In this experiment we will explore the basic concepts of how power creates light. Connect it yourself and find out!

Supplies

  • 3 Alkaline AA Batteries
  • 1 Three Battery Holder
  • 2 Single Battery Holders
  • 2 Miniature 5-volt Light Bulbs
  • 2 Red Alligator Wires
  • 2 Black Alligator Wires
  • 3 Green Alligator Wires
Lesson main content image Three alkaline batteries, AA size. The end marked with a plus sign is positive. Please use fresh batteries for optimum results. (Do not use lithium batteries.)
Lesson main content image One holder for a set of three batteries.
Lesson main content image Two holders for single batteries.
Lesson main content image Two miniature 5-volt light bulbs. (Not LEDs, because a bulb is easier to use and shows how much power you are getting from a battery. You’ll use LEDs later in this workshop.)
Lesson main content image Three wires like these. The clips are called alligator clips, so I’m going to call the wires alligator wires. It’s okay if your wires are longer, but they may get more tangled.

Experiment 1: Power and Light

Install a battery in the holder with the negative end against the spring. The two pins at the back connect with positive and negative ends of the battery.

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Connect the battery to the light bulb using two alligator wires. The bulb glows very dimly.

The light bulb glows more brightly when you add a second battery.

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The battery and the light bulb are components. When you connect them, you create a circuit. Imagine electricity flowing from the positive end of the battery, through the red wire, through the bulb, and back through the black wire to the negative end of the battery.

PRO TIP

Those Tiny Pins

If you have trouble grabbing the pins on the bulb, bend them outward a little.

What Is Electricity?

Electricity consists of tiny particles in the wires, known as electrons. They have a negative charge, but when Benjamin Franklin was experimenting with electricity (before he got his picture on the $100 bill) he decided that electricity flows from positive to negative, and we still think of it that way.

The flow of electrons during a period of time is called current.

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Your three-battery holder has positive and negative pins at the back.

Adding a third battery gives you a total of 4.5 volts. Now the light bulb glows even more brightly.

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The electrical pressure created by a battery is called voltage and is measured in volts, abbreviated with letter V. A single AA battery is rated at 1.5V. When you connect its positive output to the negative end of a second battery, they are in series, and their voltages add up.

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NOTE: If you added a fourth battery to get a total of 6V, the light would be brighter still — but might burn out after a short time, because it is designed for a maximum of 5V. All projects in this workshop can be powered with 4.5V.

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The batteries in the holder don’t look as if they are in series, but they are, because the holder contains a hidden wire. Electricity doesn’t care if it follows a zig-zag path.

What happens if you make a circuit where two or three batteries are beside each other? Now the batteries are in parallel, and their voltages don’t add up anymore. You can connect any number of them in parallel, and you’ll still get just 1.5V.

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Two batteries in parallel should last twice as long as a single battery, because they are sharing the work.

Try adding another light bulb beside the first. Now the bulbs are in parallel.

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Each of the two bulbs in parallel will be as bright as when you had just one.

When two identical components are in parallel, electricity now has a choice of two paths from positive to negative, so the current doubles, and the batteries will only last half as long.

Move the light bulbs so that one follows the other. Hold them together with your finger and thumb. The bulbs are now in series.

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Each of the bulbs in series will be less bright than before. The first will take half the voltage, and the second will take the other half.

When two identical components are in series, they create twice as much resistance for the current. Consequently, there will be half as much current, and the batteries will last twice as long.

Amperes

Current is measured in amperes, abbreviated as amps. It is represented with letter A. Small currents are measured in milliamperes, abbreviated as milliamps, represented with mA. There are 1,000 milliamps in 1 amp (that is, 1,000mA = 1A).

You can think of volts as measuring the pressure that forces electrons into a wire, while the flow of electrons per second through the wire is measured in amps.

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A diagram that shows how components are connected is called a schematic. Above are the schematic symbols for an incandescent bulb and two batteries.

Can you draw schematics of all the circuits that you have built so far?

PRO TIP

Save Your Batteries

After you finish each experiment in this workshop, unclip the red wire from the battery to break the circuit. Otherwise, the battery will run down.

THINK ON THIS

How Did It Work?

When you connected power to the light bulb, it took just a moment to react. It was warming up. This kind of light contains a thin piece of wire, called a filament, which is heated by electricity flowing through it. The heat makes it glow.

Any object that gives off light as a result of heat can be described as incandescent. So, you have been playing with an incandescent light bulb.

Incandescent lights are not used so often in houses and offices anymore. We use fluorescent lamps or LEDs. I’ll get to LEDs later.


Up Next!

Switching