# HOW TO READ CIRCUIT DIAGRAMS

this instructable will show you exactly how to read all those confusing circuit diagrams and then how to assemble the circuits on a breadboard!

for all the electronics hobbyist wannabes this is a MUST-READ instructable.

knowing how to read circuits is a very useful skill that will help you out all the time. especially if you start messing around with building little electronics projects.

In addition to reading this instructable it may be a good idea for you to read my other instructable "electronics components and what they do" to get a good understanding of what you are doing when building a project. (woops not done with this yet, i got caught up with other stuff, check back in a week or so)
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## Step 1: So What Are All Those Symbols???

here is a little guide that shows you the basic symbols for all sorts of components. its handy to keep a little guide like this around in case you forgot some. Plus, while you're beginning you might have to refer to it pretty frequently. I have boxed the most common symbols in red, these are the ones you should get to know by heart. the others you can always refer back to the guide for.

dont be overwhelmed its simpler than you think, just stay with me

## Step 2: Okay, but how is each part connected?

physically parts are connected by wires, in the diagrams you will see black lines going from one part to the next. this means that you connect them with a wire

when the black lines cross in a diagram there are ways of telling whether or not the wires should be connected to each other as shown below.

## Step 3: HOLD UP: What about Polarity?

some components to a circuit board are polarized, meaning one side is positive and the other is negative. this means you have to attach it in a certain way. for most symbols polarity is included in the symbol. in the the photos below you will find a guide to distinguishing polarity for various symbols. to find out the polarity of the physical part a general rule of thumb is to look for which metal lead wire on the part is longer. this is the + side.
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JimC22 days ago

Will someone please explain the correct way to wire a switch to this from the #14 12vdc switch input?

In step#9 it says " customer supplied switch" , just not the correct way to wire the switch, I contacted the mfg, but did not hear back from them

http://www.brookingindustries.com/instructions/FL-8ORFiP.pdf

HarishB14 months ago

very helpful sir.i am an electronics and communication student.thank u.

jasongervasio19914 months ago
I'm it trying to be a cynic, but I think that the diode was improperly labeled in the schematic. By all means, correct me if I'm wrong, but aren't LED's supposed to have two little lightning bolts along side of them?
STEMsheets5 months ago

You may find these customizable flash cards useful for learning circuit symbols: Circuit Symbol Flashcard Maker

FRIENDOFGOD6 months ago

VERY helpful...One question though...If when reading a diagram if the wires are connected on the diagram BEFORE a switch post but go right into a switch post after the connection when you are wiring do you solder mid wire or at the switch post thing?

squid_matic9 months ago

This is helpful, especially for those who want to learn more about circuitry, and for us engineers to further enhance our ability and familiarization on symbols and types, Great!

spirit x11 months ago

whats the symbol for a transformer

9 months ago

Symbol for transformer is:

CRASH MA5TER9 months ago

i like it

jkleyn10 months ago

Thanks! Pure simple and Clear.

spirit x11 months ago

can some one tell me how to use a 8 pin mini transformer

spirit x11 months ago

whats the symbol fora transformer.

K Nyarko11 months ago

shallowman1 year ago
Great intro, however I would really like to see you explain a more advanced circuit schematic.
okhajutt1 year ago
Nice
GeoEg1 year ago
Excellent Intro!
ndav1 year ago
excellent introduction to circuits, thank you
Malik_Khawer1 year ago
very nice Thanks to giving me ausefull information
ash3031 year ago
good stuff. Thanks and keep it up!
sbroom91 year ago
great site easy to understand glad i found it
spikec1 year ago
Nicely done. Your series of 'ables is awesome, thanks!
bvillamor1 year ago
thank you for the information
bvillamor1 year ago
jamanda2 years ago
THIS WAS AMAZING!! Thank you so much ! This helped my land an electronic assembly job !! KEEP IT UP!
drumerdude2503 years ago
apaterson13 years ago
i'm struggling with one particular symbol it looks like lots of connected ohm signs or some interconnected circles can you tell me what this is *note* it is not an inductor or a coil
4269srd3 years ago
i like it! but you should go into a little bigger schamatics. im going to see what other things u have. thanks!
RANDOMFISHYFACE4 years ago
the symbol for Diode(D),Photo and Gate,AND look exactly the same. what is up with that?
3 years ago
Yes. that's a mistake. The symbol of AND gate looks the same as NAND gate when you remove the dot near the output.

Symbol for NOR gate should have a dot similar to the NAND gate near the output.
4 years ago
They aren't. You just can't see it because of image quality and size.
4 years ago
no sir they are the same if you click on the enlarged version (www.instructables.com/files/orig/FIW/DFTY/FW39JKC5/FIWDFTYFW39JKC5.jpg)
then zoom in on that area you will see that they are exactly the same
PJcollazo4 years ago
Very helpful! I didn't remember this from a couple years back.
PKTraceur5 years ago
I still don't understand how microchips, like 555 timers and those other blac rectangles with like, 20 leads work. Nor do I get caps. For that matter, how the heck does electricity flow? Oh well, camera tasers are still awesome. -PKT
aplauche (author)  PKTraceur5 years ago
micro chips are very complicated small circuits. they are built out of the same things as most circuits: resistors, capacitors, transistors, etc.... just shrunk way down. hence micro. so really a micro chip is just a very tiny circuit board pre-made for your use
5 years ago
Your the first one in 3 years to make microchips actually make sense. Thank you. -PKT
Alfa_Romeo5 years ago
Great post this one, hope in your next post you will go "deep" in this matter
tundrawolf5 years ago
Boy, that circuit looks almost edible. *Drools* resistorssssssss
sageserver5 years ago
to help people understand how these parts work go to http://www.falstad.com/circuit
It taught me about ac curcuits.
5 years ago
There are some variations for parts. Like leds can be a diode with 2 arrows going out. regarding the schematic for the flashlight, usually theres not a resistor becuase resistors just throw away current, and flashlights(bulb type) are not LEDS.
aplauche (author)  sageserver5 years ago
i know, but i wanted something that could be constructed with very little cost on a simple breadboard so people could get the experiance. this instructable really isnt about the flashlight, its about understanding schematics like the title says. i just chose a simple led you could turn on and off so that people could really see that their circuit worked
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