Parallel and Series Circuit

Introduction: Parallel and Series Circuit

There are two basic types of electrical circuits; series and parallel. A complex circuit can consist of sub circuits of each kind.

Step 1: Series Circuit

In a series circuit, the path of electrons from the negative (-) side to the positive (+) side goes through all the electrical components of the circuit. Another way to think of this is that if you open the circuit at one point, on either side of a component, there is no complete path for the electrons to follow from - to + for any of the components. A good example of this for those of you old enough to remember is the old style Christmas lights where if one light were to burn out, the whole series of lights would go out. Series circuits are used extensively in electronics but rarely by someone who is providing power to electrical components such as supplying power to a group of lights as in the case of low voltage LED lights sold by Berkeley Point. A simple schematic of a series circuit containing three electrical components (represented as light bulbs below - icky incandescent light bulbs at that), is illustrated below:

Series Circuit:

Step 2: Parallel Circuit

In a parallel circuit, each component has its own direct path to both the negative (-) and positive (+) sides of the circuit. A simple schematic of a parallel circuit is shown below. In actually wiring the LED lights from Berkeley Point, as long as the red leads from the lights are connected to a wire that goes directly to the positive (+) side of the power supply and the black leads are connected to a wire that goes directly to the negative (-) side, you have wired the lights in parallel. If you follow the wire path back from a light to the power supply, it can "T" to other lights but should not go through any other lights. If your feed wire is similar to the Belden wires provided by Berkeley Point in so far as they consist of a red and black wire. In a parallel circuit, you will never have a black wire connected to a red wire (contrasted with example of series circuit shown above). Further, as long as you can follow a path from the red wire of a light back to the positive (+) side of the power supply through red wires and the same through black to the negative (-) side, you have wired in parallel. A group of many lights may have all their red leads connected together with one red (+) feed wire and all their black leads connected together with one black (-) feed wire.

Parallel Circuit:



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    22 Discussions

    I have 5 AA Batteries that run at 1.2V and 2.5 Amperes each. I want to wire them together so that the total current output is the same as a lead acid I want to replace; which is 6 V 2.5 Amps. Would I have to wire them together in series or in parallel to do so?

    Just wondering if anyone can help me. I am setting up an array of LEDs that will include a few colours. The problem is that most of the leds have the same forward voltage (2.0) but the blue is different (3.6). Can I run a series that includes diodes with different voltages?
    My source is a 12VDC. What I would like to do is run 2 blue 2 red for a total of 7.2 + 4.0 = 11.2 Volts with a resistor, rinse and repeat in parallel until I finish the array.
    Any chance this can work?

    Series circuits add the resistance of the circuit, while parallels split the voltage. However, the light bulbs glow better in a parallel circuit.

    yeah i'm pretty new to the whole led part of electronics and i was wondering something, if you have four leds all 3v, and put them in a series on a 12v, would i need a resistor

    I am pretty new to electronics, however, the negative lead from the negative side on the battery connects to the positive pole on the light bulb ending up with the negative pole on the light bulb connecting to the positive pole on the battery. Does this matter? Thanks.

    1 reply

    finally somewhere to send people if they do not know the difference between them. i had made a special document that i posted in comments when people asked these questions. anyway a lot of people dont understand this so it is good that you have done it

    Geez, thank you so much! Trying to figure the simple stuff is sometimes way more difficult than it should be, thanks for being a navigator!

    I run an electronic security dept at a college and have 2 guys for instance, 1 with a degree in electronics from ITT tech who doesn't understand these theories and another who says he's a $30 a hr tech who can't spell basic electonics.Both hired by my boss. I'd like to have a place to direct my guy's to look for instruction when I don't have the time. Infact I'm going to have them check here for the projects to hopefully get them to want to inprove their skills.

    I'm most grateful to tjayfowler for posting this. I am an older beginner and found this site eventually by googling. I'm relieved to have found all levels of electricity and fun projects to do. Brenda

    Relax Dude- Surely you have discovered that many who use the web don't have a clue about basic circuits, much less than basic electronics. Perhaps the author of this instructable runs into them often enough, they wanted an example to point the people to. Looks like seeing a potential need and extending an effort to fill it, not arrogance. IMO it would have been simpler to Google for an existing illustration to create one from scratch. I would admit using every day objects and color may help the non-tech oriented person better than a BW schematic would. s.

    6 replies

    Well I have to take your point. I was going to post things like "How to find the the answer to your Forum question by using Google" and "How to use Word to spell-check your posts". But, I couldn't balance sarcasm with being imformative to my satisfaction and gave up...
    I suppose that I was thinking you would have covered this in school by the age of ~11, which covers most people on this site.


    while I (cough) would have found this very(cough) usefule a few (cough) months ago and think you went a little overboard on your first reply, I do have to admit I have a lot of difficulty saying I was wrong and respect you for doing just that.

    So arrogant. So pretentious. I must post a set of illustrated instructions called, "How to avoid being a condescending ass in 3 easy steps." Step 1: Grow some empathy. Step 2: Take empathy grown in step 1 and apply liberally. May also be taken internally, though be sure to check your local legislation concerning the ingestion of empathy. Step 3: Wait until you feel the effects of the recently applied empathy before posting comments. Step 4 (optional): REPEAT AS NECESSARY!

    It's nicely done, but really text-book basic (and text books often go a bit further and have a switch). It's only the lack of content I object to. L

    I think you are confusing arrogance with utility... So sour... so bitter... so, so lemonie.

    Some people might need to take a deep breath, and then practice thinking about how *others* might view the world. And practice using non-insulting language. I found this instructable both useful and clear. Thank you.