Jow Forums if I have a bunch of LEDs, how do I get them to flash one by one? Do I have to use some capacitors?

Jow Forums if I have a bunch of LEDs, how do I get them to flash one by one? Do I have to use some capacitors?
I don't own a function generator.

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1) Johnson decade counter
2) Monostable 555 timers arranged in a sequence (each 555 triggers one LED briefly)

been a while since i mess with electronics but you might be able to use a shift register for that. its messier but werks

Oh man, this brings back memories. Sadly I forgot about how most of that stuff works. Are you using arduino?

you'll probably need a resistor and capacitor, but the 555 is key. look it up on google, plenty of examples of how to construct such breadboard circuits (even video tutorials on youtube).

I was trying to do it as simply as possible, so no microcontrollers or anything.

If he was it would be trivial. For his sake I'm going to assume not.

If you had a transistor like a bjt then you could make a switch turned on an off with a few caps. Simpler just to buy a 555 though.

Just unplug and plug their respective wires :)

Couldn't be bothered to draw a better image, but I remember this same exact challenge from high school over 12 years ago. You can chain together 555 timers so achieve that relay flashing.

Pin 2 (trigger) is connected to a button which is itself connected to ground. Pressing the button activates the first LED

Pin 3 sends output to the LED but also is connected to pin 2 of the next 555 timer, which does the same thing over again.

R & C represent the resistor and capacitor combination that you use to determine how long the LEDs stay on. That time constant is determined by 1.1 x R x C

So to have the LED stay on for 2.2 seconds(ideally.. manufacturing imperfections could affect this duration), you could use a resistor of 10kOhm and a capacitor of 100 microFarads.

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I don't have any switches but I do have some transistors and a few op-amps.

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You're going to need resistors and a capacitor if you want this done minimalisticly. Google: flip-flop circuit

hey so lets just say what if i hypothetically forgot whether my transistors are PNP or NPNs, what would i need to do to figure it out?

Let me list everything I have:
>LEDs
>regular diodes
>fuckloads of resistors, all different values
>a bunch of capacitors of different values
>a few transistors
>some op-amps
>a potentiometer

DING DING DING WE HAVE A WINNER

Most cheap multimeters have a testing grid for it. If not, you need a breadboard and an LED to check for that.

Also, you could just google the serial number on the transistor if it is still legible

Shhh.
Don't tell anyone I told you but...
is where the cool kids club is.
Shhhh.

Figure out how to test a diode (meter or test circuit)
Then realize a diode is a PN junction

This is more /diy/ than Jow Forums actually.

Regardless, a common way is to use 3 555 ICs that trigger one another in a loop.

Shit. Make that 20kOhm and 100 microFarads. Fucked up the math

Using only op-amps it's possible to build a function generator. I don't remember the details, but we built one in electronics lab once. You could probably find instructions online...