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I am frustrated.. help me.

E

Eli

Super Moderator | Elite Member
And I can't fscking get it to work. What the hell am I doing wrong? It's 2 resistors and a cap, not exactly rocket science.

R1 goes between pins 8 and 7, and R2 goes between pins 7 and 6. C1 goes between pins 6 and ground. Pin 1 is ground, pin 8 is +5v, as is pin 4. Pin 2 is connected to pin 6(astable mode).

Simple. I'm using a 1k ohm resistor for R1 and a 10k pot for R2(so I could theoretically adjust the blink rate), and a .1mf cap for C1.

So why the fsck does my LED sit there and stare at me, not blinking? I thought maybe I fried the 555 chip messing around, so I went and got another.. same problem.

I'm pulling my hair out, I can't believe I'm having this much difficulty.. what the hell am I overlooking?

😕😕😕😕😕

I'm following the directions found here....
 
Did you check to see what the frequency it would blink at is? I used the formula on the link with your numbers and got ~685 Hz, which would be way too fast to see. But it's late, so you might double-check my numbers.

Edit: Is C1 0.1 microfarads, or 0.1 millifarads? I read it as microfarards the first time, which gives the 685 Hz. If it's millfarads, that gives you 0.69 Hz, which would be fine.
 
Aren't Microfarads labeled as MFD on the caps? (as opposed to uF). I can't find the schematic of the last lab I did with a 555, so I don't remember what I did that worked.
 
Finally, I got it working. Jesus H. Christ.

It was my capacitor.

I had tried other values, but I must have had something else wrong at the time.

The 0.1mf cap I was using doesen't seem to work. Well, it lights the LED.. but using it, the frequency must be so fast that I can't see it or something.

Using a cap in the 20 - 500uf range, and getting good results now..

I'm new to all this electronics stuff, even though I know the basics.. I'll get the hang of it.

I've got a bunch of DIY kits on order, to help further my knowledge and soldering skills.. It interests me a lot. I'll just consider this a small bump in the road and move on. 😉

Often the most simple things are overlooked.. I knew I was building the circuit right, I just couldn't figure out why the fsck it wasn't .. blinking. Now I know. 😀
 
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