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Electronics 101

Basic instruction, Making an LED light, and steps for the future.

By James Newton @ MassMind.org

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Electronics. are. EVERYWHERE!

Our world today depends on Electronics, from iPods to Power Stations, Laptops to Defibrillator Paddles.

OMG the Internet is Electronic!

But how does it work? Do you know? Can you get through a modern life without knowing?

We hope you are curious and want to know. Because Electronics can be very fun. And each part of it is easy.

This class will cover the basics, teach you to solder, and provide you with some options for learning and doing more.

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LED Throwies

http://www.instructables.com/id/LED-Throwies/?ALLSTEPS

An inexpensive way to add color to any surface in the neighborhood. �A Throwie consists of a lithium battery, a 10mm diffused LED and (optionally) a rare-earth magnet taped together.

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LED Throwies: �Parts

10mm Diffused LED cost: ~$0.20 per LED in quantities. Comes in red, blue, amber, white in both diffused and clear. Diffused works better �Sources: HB Electronic Components .

CR2032 3V Lithium Batteries cost: $0.25 per battery in quantities. With the 2032 Lithium battery, depending on the weather and the LED color, your Throwie can last a week or more. �Sources: CheapBatteries.com

(optional) 1/2" Dia x 1/8" Thick NdFeB Disc Magnet, Ni-Cu-Ni plated Cost: $13.00 per 25 magnet.�Sources: Amazing Magnets

Tape. Just about any sort will work. Clear packing tape is probably best.

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LED Throwies: �Assembly

Grab the LED and notice that one lead is longer than the other.
Place the battery between the LED lead so that the long lead is on the side of the battery marked "+". Don't let the short lead touch the batteries "+" side.
You can wrap that with one layer of tape, or just add the magnet and wrap it in tape.
Done!

Longer lead

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Electricity Is Like Water.

Electricity flows in a wire just like water flows thru a hose. Water spraying is like electricity arcing.

Resistance is what stops or slows it. A kink in the hose is just like a resistor in a circuit.

When they flow, the pressure drops, when you resist the flow, it rises behind the kink. In electronics, we call that pressure Voltage.

The amount of flow; the volume of water or number of electrons, is called Current in electronics.

For more watch this video:�https://youtu.be/NqZZ-S74EFA

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Ohms Law: �Volume = Force / Resistance

Name Symbol Units

Force ( F )

Resistance ( R )

Volume ( V ) Units/Time

Name Symbol Units

Pressure ( P ) PSI

Flowrate ( F ) GPH

Resistance ( R ) OHM

Name Symbol Units

Voltage ( V ) VOLT

Current ( I ) AMP

Resistance (R/Ω) OHM

OHMS LAW: �V = I * R

or

I = V / R

or

R = V / I

What is the Force, Resistance, and Volume here?

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A Simple Circuit: LED

This link leads to a live simulation of a simple circuit:

http://techref.massmind.org/techref/io/led/single_sim.htm

Where is this resistor in our "throwie"? It's inside the coin cell battery and the LED! Using an extra resistor would allow us to use a higher voltage source, like a USB port, or a 9 volt battery, without blowing up the LED.

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More components: Resistors

Resistors "resist" the flow of electrons, just like a kink in a garden hose holds back the water. That also keeps the pressure high behind the kink and reduces the flow after the kink, just like a resistor keeps the voltage higher on the side toward the positive and keeps the current flow low in the loop between positive and negative sides.

A large resistance clamps down more, a small resistance just holds it down a little. Using the right value, you can get just the voltage and current you want for other components, like the LED even from a bigger power source like a USB cable.

Because resistors are tiny little things, it's really hard to print their value on the case, so there is a color code which encodes the value. It's a pain and we don't recommend using it. Just buy a good cheap multimeter and use that to measure the actual resistor value. The "Equus 3320 Innova" is commonly available and not bad for about $20.

If you want to find a specific resistor in a bin, use this webapp to see what it should look like:�http://techref.massmind.org/techref/resistors.asp

Resistors also come in only certain values, to get a specific resistance value in a circuit, sometimes you need to combine 2 or 3 resistors. The app helps with that as well.

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Math. Or why you learned Algebra!

Math is your friend
Examples:
I = 2 mA*
R = 1000 Ω
Remember V = I x R
V = 2 Volts

Try this one:

V = 9 Volts
I = 2 mA
R = ? Ω

*mA equals milli amps also known as 1/1000 amps.�So 2mA is 0.002A. Don't forget to convert!

So if you want 2mA of current to flow, and you know the resistance is 1000 ohms, you need 2 volts.

Let's say you want to run an LED from a 9 volt battery… what resistance should you use to avoid frying the LED? Most LEDs can handle about 2mA

Can you find a resistor with that value?

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MORE TO EXPLORE

Soldering 101 - Learn to make permanent electronic circuits

Soldering 102 - Make the Makerbot LED badge

Soldering 103 - The BOB Panel board.

Digital Logic Tutorial

http://techref.massmind.org/techref/logic/tutorial.htm

Online electronic circuit simulations

http://www.falstad.com/circuit/e-index.html

Cool stuff you can make:

http://learn.adafruit.com/

More:

http://www.circuit-fantasia.com/index.html