This instructable is a step by step guide to design and simulate a simple electronics project on 123D Circuits using a virtual breadboard design which is linked to schematic and layout views.

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## Step 1: Create an account

Go to 123d.circuits.io and fill in your user name, email and password.

## Step 2: Creating a breadboard circuit

Once you are signed in, you'll see your dashboard.
From here you can:
1. Make new circuits
3. Import circuits from Eagle

>> click on "New circuit"

Now you have to:
2. Choose if it's a regular schematic or one with breadboard view and simulation
3. Click on "Create New!"

## Step 3: Editor overview

Here is an overview of the editor window:

1. The views: Breadboard, Schematic, PCB, Bill Of Materials
2. The Arduino: you can upload code, and connect components to the terminals. This can also be used as a power supply.
3. The breadboard: you can place components on this.
4. The controls.
5. Tool box: take here the basic components you need.
6. You can search for the components that aren't in the toolbox.
7. Chat box for collaborative editting.

The first included image shows what the internal connections of a breadboard are.

First delete the Arduino because we don't need it in this instructable.

Add an LED, a resistor and a button from the tool box and place it on the breadboard.

Now we want to add a power supply. Click on "Search Component", scroll down a bit and add a 9V battery. Connect everything up as can be seen in the screenshot.

We also need to set the resistor value. First we need to calculate the required resistance.

R=U/I    Resistance=Voltage/Current

The maximal voltage over an LED is 1.7V, and the Voltage of the battery is 9V. So the Voltage over the resistor must be 7.3V. An LED uses 20mA = 0.02A when on.

R = 7.3V / 0.02A = 365Ohm

Click on the resistor and set it's value in the inspector you can see at the bottom of the screen.
bclamore10 months ago

I've just opened an account and was trying to create a simple circuit, but the breadboard won't let me make the final jumper wire connection. I drag it, but the wire just disappears, Can't find anything in the Help. Can I impose on you?

Ben Finio1 year ago
Anyone know if you can force a "top-down" view of the breadboard components so they don't take up so much space? For example, notice how the quasi-3D view of the LED in the image above makes it obscure several adjacent columns...that was my biggest complaint the first time I tried to use Fritzing (so bad, in fact, that I gave up using it because things like potentiometers and MOSFETs were just enormous), and I'm wondering if this would be a good alternative for realistic breadboard diagrams that might have tightly packed components.
1 year ago
ya, its really annoying but theirs another one i kinda like, i'm wondering if its accurate but it still works for most things. http://www.falstad.com/circuit/
razamatraz1 year ago
I haven't taken much of a detailed look yet. I'm wondering, since it can simulate Arduino does that mean that it can also simulate the ATMega line of microcontrollers natively? The 328 at least since that's what an Arduino contains?

I like the idea of an Arduino but I much prefer to use these units in native mode.
onitreb1 year ago
My LED blows up using a 350Ohm resistor!
1 year ago
At what voltage? You have to remember, both resistance and voltage play a factor! At 350-Ohm, You should be no higher than 5V supply.. real-world, I use 220-ohm resistors for 5V output. 12V, nothing lower than 2.2K.
123D Circuits (author)  onitreb1 year ago
You are right that was a mistake. The voltage over the LED is 1.7V not 2V. I corrected it. Thanks for the heads up!
harleyguy1 year ago
I am just getting started teaching myself about electronics, so I can fix my CB & Ham radios. This just what I need to help me learn about how and why things work. Thank you
zakatak1 year ago
First, thank you. This is great. I can try a whole bunch of things with out explosions in my face. I have never managed to get into electronics before. I have certain things that I think I know about electronics, but I haven't tested this knowledge.

I had a problem with this instructable (as noobs will).

My LED kept [simulating] explosion. Then I noticed that the resistor color bands change in the images. Now in my limited understanding of electronics I believe that the colors on resistors mean something, so I found [http://www.digikey.com/us/en/mkt/4-band-resistors.html] which let me enter the colors of each band and it looks like we should use 420 Ohm for our Resistance setting to match the screen. Is that correct? It may be beyond the scope of this instructable to explain how to determine this number, but can you recommend a source that can help guide us in making this?

Thanks again, this is a really nice way to learn some about electronics with limited risk.
1 year ago
There are loads of online LED-Resistor calculators - my personal favourites are: http://led.linear1.org/1led.wiz for a single LED, or http://led.linear1.org/led.wiz for arrays of LED's. They are by the same people, so each has a link to the other.

1 year ago
Excellent, that's what I was hoping for. Wading through Google search results when you are a noob is overwhelming. Not because there is a lack of information, but because it's hard to keep things in context when you do not yet have any context to keep things in.

1 year ago
You're welcome.
1 year ago
It seems this way to me too. Here's the comment I was going to post before I saw that you already addressed this problem.

I think there may be something wrong with this instructable? (It's probably me doing something wrong.)

If I use a 350 ohm resistor my LED overloads. I am seeing 21mA and 1.74 V across the LED (not 615 mV like in the last page).

If I use a 421 ohm resistor as the color code in the later pictures indicates the LED works correctly. I get 17mA. (and 1.74 V across LED still.)
1 year ago
Also, I wonder if there is a way to see the detailed specs on the various components . . .
1 year ago
I think if you load the project up (I right clicked the name in the iframe of step 7 [http://123d.circuits.io/circuits/19390]) and hit the "fork" button you actually get your very own copy of it to investigate.  So that's pretty cool and actually pretty helpful.
manuka1 year ago
You may care to at least nod to the free "PEEBLE" (Picaxe Electronic Bread Board Layout Emulator) layout software. It suits a huge variety of components, although it does not simulate their action. It's available on line => http://www.4dsystems.com.au/downloads/pebble/P_for_IE.html or can be downloaded for local use.

FWIW I still use (educationally) the UK sourced  "Crocodile Clips" simulation software that was first released some 15 years back!  It's now owned by Yenka - check =>http://www.yenka.com/technology/
Raphango1 year ago
Raphango1 year ago
Pretty cool! Gonna try it! =D Results later! ;)
Kiteman1 year ago
Is it free to create an account?
123D Circuits (author)  Kiteman1 year ago
Yes, account will always be free for open designs. I you want to make your designs closed source, you need a subscription.
1 year ago
And how much would that be?

I can see this being useful for schools - do they do educational subscriptions?
123D Circuits (author)  Kiteman1 year ago
You can find the different subscription tiers here: http://123d.circuits.io/pricing

Educational discount if of course available. Just email us.