LED Chaser Circuit Without IC

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Introduction: LED Chaser Circuit Without IC

About: I make how to and life hack videos and share them on my YouTube channel: https://www.youtube.com/c/newpew

In this Instructable I show you how to make a simple LED chaser circuit. The special thing about this circuit is that it does not use an IC (Integrated Circuit).

Video tutorial

By using different resistors, capacitors and transistors, I succeeded in this project to make a circuit that lights the LED lights one by one. The base of both the transistors are connected to + connection through resistor. Any one transistor will get activated first. (this is because no transistor is exactly similar to other one). Lets assume transistor 1 turns on first. When the transistor turns on the collector pin gets grounded and led at its collector lights up. Also the capacitor starts to charge through ground provided by 1st transistor and the 4.7 K resistor at the base of 2nd transistor. Since the 1st capacitor is charging it is taking current from the 4.7 K resistor which is at the base of 2nd transistor. The base of 2nd transistor has no current to activate its led. At some point 1st capacitor will charge up. And when it does so, there is no more current flowing through it. Now there is enough current that can flow through base of 2nd transistor. The 2nd transistor gets activated. (Including the led connected to its collector). The process repeats and when the 2nd capacitor is charged the third transistor is activated. Then the first, second and so on.

Supplies:

  • 3 x 3 LED lights (any color you want)
  • 3 BC547 transistors
  • 3 330 Ohm resistors
  • 3 4.7 K resistors
  • 3 100 uF capacitors
  • Electrical wire (small pieces)

Step 1: ​Connecting the Transistors

For this project I used BC547 NPN transistors. In the attachments is an image with the pin assignment to keep it clear. Bend the collector and base connections of all 3 transistors to the left. Bend the emitter pins to the right and solder them together.

Step 2: Mount the Capacitors

As described in the introduction, capacitors are placed between the transistors to "control" the circuit.

  • Solder capacitor 1 + to the collector of transistor 2
  • Solder capacitor 1 - to the base of transistor 1
  • Solder capacitor 2 + to the collector of transistor 3
  • Solder capacitor 2 - to the base of transistor 2
  • Solder capacitor 3 + to the collector of transistor 1
  • Solder capacitor 3 - to the base of transistor 3

Step 3: 4.7K Resistors

Solder a 4.7K resistor to all 3 base connections of the transistors. Connect the other ends of the resistors together.

Step 4: 330 Ohm Resistors

Solder a 330 Ohm resistor to all 3 collector connections of the transistors. Connect the other ends of the resistors together with the ends of the resistors from step 3.

Step 5: Prepare the LEDs

Because I like it looking I chose to mount the LEDs in a kind of star shape. Of course this can also be done in a straight line or another shape.

Solder the LEDs together per group of 3. Note that the anodes and cathodes are in the same direction.

Then solder the cathodes (-) of the three groups together.

Step 6: Connect the LEDs to the Circuit

Solder a red wire to the 3 plus connections of the LEDs. Solder a black wire to the joint minus connection of the LEDs.

Solder the other ends of the red wires to the collectors of the transistors. Sequence determines whether the sequence of the LEDs is left or right (reminds me or switching phases XD)

Solder the other end of the black wire to the connected emitter terminals.

Step 7: Connecting the Battery

Solder the red wire from the battery connector to the connected ends of the resistors. Solder the black cable from the battery connector to the connected emitter terminals of the transistors.

Step 8: Ready

Ready! Just click on the battery and the LED chaser will work!

The electrical diagram is in the appendix.

With the last few Instructables came the question for an electrical schematic of the circuit. Since I have no experience with drawing diagrams, I am very curious about what you think of this! Is this scheme well drawn and is it useful to you?

Video tutorial

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    33 Discussions

    0
    bf1104
    bf1104

    Question 1 day ago

    Hi... As everyone else has said, it's a great looking project. I have a quick question if you don't mind? How would I go about slowing down the switching from one set of leds to another?
    Thanks in advance

    0
    john.ostermann
    john.ostermann

    5 days ago

    Can anyone answer this: if you chose to run it off of a 12V system, as in a car, would any component/s need to be changed bc of increased voltage (12V vs 9V)?

    0
    Mad4400
    Mad4400

    Reply 1 day ago

    You might raise the value of the 3 x 330 Ohms resistors to 470~510 Ohms to protect the LEDS from over current..

    7
    Mad4400
    Mad4400

    10 days ago

    Thanks for providing a schematic with your project this time. Typically the convention is V+ at the top and ground at the bottom. Following this rule, I have redrawn it for you.
    https://i.imgur.com/iNf18ds.png

    Ignore the comments from the "clever" people, if they were truly intelligent they would have offered some helpful input.

    A discrete device (or discrete component) is an electronic component with just one circuit element, either passive (resistor, capacitor, inductor, diode) or active (transistor or vacuum tube), other than an integrated circuit.

    9V LED chaser.png
    0
    Rukbat
    Rukbat

    Reply 1 day ago

    Thanks for the schematic, Mad - saved me the trouble. The original was definitely a schematic, but your redo made it clear at a glance that this is a ring oscillator. (And ... an integrated circuit is 2 or more things integrated [usually] on the same silicon die, which is why a transistor doesn't qualify.)

    0
    gbansen
    gbansen

    Reply 6 days ago

    Thanks for your drawing, but to be honest as an electrician I find his drawing much easier to follow.

    0
    prabbittablet
    prabbittablet

    Reply 6 days ago

    If you took his (New Pew's) drawing and turned it 90 degrees clockwise, it'd have the positive/supply at the top and the negative/ground at the bottom, same as Mad4400's. Personally, I prefer Mad440's, however, due to the fact that there's no lines that cross.

    0
    KevinH403
    KevinH403

    10 days ago on Step 8

    Since when are transistors not considered IC’s?

    3
    prabbit237
    prabbit237

    Reply 9 days ago

    Probably since one transistor alone does not a circuit make.

    Now there ARE IC's in that form factor. Dallas temperature modules, for example .Anytime you need to make a block diagram on a datasheet, that implies there are MANY parts inside. So even if it's just a transistor and a resistor on the same chunk of silicone, it's an IC.

    0
    JohnW51
    JohnW51

    Reply 6 days ago

    jc_0142 - Absolutely correct. An IC can also include diodes of all types and small value capacitors. Typical ICs these days can contain thousands of transistors and other components. In the case of microprocessors, they can contain millions!

    0
    prabbit237
    prabbit237

    Reply 4 days ago

    "Millions"? *waving hand* That's so twentieth century. Try billions and even trillions :)

    https://en.wikipedia.org/wiki/Transistor_count

    Looks like the Dual-Core Itanium 2 was the first to top one billion transistors in 2006 but if we're talking resistors, diodes, caps, etc, the Itanium 2 McKinley may have topped the one-billion mark in 2002 (had around 200 million transistors) and the Itanium 2 with 9MB cache in 2004 had around 600 million transistors. Just all depends on how many non-transistor parts needed to be on the chip for every transistor.

    But the current record holders are: "As of 2019, the largest transistor count in a commercially available microprocessor is 39.54billion MOSFETs, in AMD's Zen 2 based Epyc Rome, which is a 3D integrated circuit (with eight dies in a single package) fabricated using TSMC's 7 nmFinFETsemiconductor manufacturing process.[1][2] As of 2020, the highest transistor count in a graphics processing unit (GPU) is Nvidia's GA100 Ampere with 54billion MOSFETs, manufactured using TSMC's 7 nm process.[3] As of 2019, the highest transistor count in any IC chip was Samsung's 1TBeUFS (3D-stacked) V-NAND flash memory chip, with 2trillion floating-gate MOSFETs (4bits per transistor).[4] As of 2020, the highest transistor count in any IC chip is a deep learning
    engine called the Wafer Scale Engine 2 by Cerebras, using a special
    design to route around any non-functional core on the device; it has 2.6trillion MOSFETs, manufactured using TSMC's 7 nm FinFET process." (from the Wikipedia article.)

    0
    JohnW51
    JohnW51

    Reply 6 days ago

    prabbel237 - Yes, that's true. But a single transistor with no other circuit on the die is just a transistor. Would you consider a Darlington pair an IC? I've never thought of it as such, but i guess in the broadest sense it is since it is two transistors connected together and sometimes with integrated (there's that word) resistors.

    0
    prabbit237
    prabbit237

    Reply 4 days ago

    *augh* No, I wasn't meaning to use a sock-puppet with the reply "I would say anytime you've "integrated" more than one part..." I have a few Gmail accounts for various purposes that are similar in name and I didn't realize I'd logged in to here with a different one.

    0
    prabbittablet
    prabbittablet

    Reply 6 days ago

    I would say anytime you've "integrated" more than one part into a single unit, it's an IC. So yes, a Darlington pair would qualify as you could make a Darlington pair out of two discrete transistors as well. Of course I'm ignoring "components" like wiring that simply joins other parts together. So a transistor or diode may have wires embedded into the housing but they still aren't ICs. But two or more transistors or a transistor and resistor, etc, all in one package, would be an IC IMHO (even if a very simple one.) For the most basic usage of the term, they don't even need to be on the same piece of silicon as long as they're in the same package.

    Think of the term "black box" where you're only worried about what goes in and what comes out. If the black box can not be replicated by a single discrete component with a single function but would need multiple discrete components to duplicate it, then it's an "integrated circuit." A diode can't be broken into more basic components. A resistor can't be broken into more basic components. Same for an inductor, capacitor, etc. Even a transistor can't really be made by connecting two diodes together, even if it can be thought of as such.

    4
    jc_0142
    jc_0142

    Reply 7 days ago

    A single transistor is not an IC, even 2 transistors connected as Darlington is still called a Darlington transistor. IC stands for Integrated Circuit, it came years after transistors were invented. Before IC's, there were attempts to put modular circuits together called hybrids, basically some standard functional or propriety circuits (Dolby Labs used to sell or licensed their propriety circuit this way) on a tiny circuit board that's pretty much what IC now replaces. You can have an array of transistors or resistors in an IC package, hence transistor array or resistor array and you can call them an IC, but not when you have a single transistor.

    0
    bruceyheli
    bruceyheli

    Question 5 days ago

    How many led's can be used? This looks like a nice quiet system I can use. Place led,s on spokes of a stationary wheel to give impression it's turning. Can I Daisey chain some how to more led's ?

    1
    throbscottle
    throbscottle

    6 days ago

    Nice and elegant circuit. Such a tidy build too!
    I see this and think of all the people who would need to program an arduino to do this. I like your way better :)

    0
    and7barton
    and7barton

    6 days ago

    And it worked. Every thing I ever built never worked. I even once built an amplifier that made the signal quieter. Now, that take some doing.

    0
    throbscottle
    throbscottle

    Reply 6 days ago

    Not difficult. I have made many amplifiers that made the signal quieter!