555 timer beginner circuit help

Hello,

I am the IEEE Project Coordinator at my university and I am trying to teach beginners to electronics the concept of bread-boarding and how to use the 555 timer.
Now I consider myself a pretty knowledgable person in electronics and this is why I'm kind of annoyed.

I was going to show them this circuit , BI-POLAR LED DRIVER Circuit but for some reason it just isn't running. I have it wired up like the image but it just won't run!

Any help?

Have you tried swapping parts out or even swapping out the breadboard? I know from my school days that students often put bad parts back in the parts drawers. It shouldn't take long to completely start over with new parts.

Yup, everything has been tried with new parts, even the power supply

Make sure the 33K is connected to output, not 9V.

I made up that exact circuit, and it worked. Both LEDs flashed. Only one flashed when powered with 5V.

it just isn't running

What do you mean? No LEDs flash? Just one? One or both on all the time?

Roger that, yuuup its connected properly

Nothing happens. No flash, no nothin.

any other ideas? Maybe the diagram is wrong?

How could it be wrong if I just got it to work?

Maybe post a clear photo.

What?! Really? Maybe I'm not as good a breadboarder as I thought I was.
I should point out that I don't have a bi-color led like the thing says, so I'm just using two leds set up like the diagram.

This is the best picture I can get.

funkyguy4000:
I should point out that I don't have a bi-color led like the thing says, so I'm just using two leds set up like the diagram.

That's what I had.

It looks to me like you have something connected to pin 5, which is NC on the diagram.

Is that 10 uF cap in the right way? It looks not, from the photo.

Hmm don't know how that wire got there.
After I removed it, I switched the cap around. Still doesn't work.

This is my setup, which works:

Hmm, well now I have it working! I'll look over the diagram to see what I did wrong. Thanks a bunch!

Interesting....
When I connect up the 2nd led in the backwards direction with the resistor going to GND. the whole circuit turns off. I thought that those two resistors might just be shorting out the whole circuit.

Is that whats going on?

the led is probably shorted out.

This is a little different situation isn't it? The LEDs might be in parallel, but they are never on at the same time since they are reversed, so this wouldn't apply, right?

funkyguy4000:
When I connect up the 2nd led in the backwards direction ...

I assumed he meant he flipped one of the two LEDs so now they are both in parallel.

So with a 5v supply maybe 12 at a push what is the best way to power 256 ir led's? all with the same signal a pwm signal. After much head scratching and taking apart a 60 led torch to find all led in parallel and one resistor, i decided on a constant currant led driver and to put them in groups of around 700ma(what the driver is rated at). Now the led are rated at 20ma maybe more for pulsing, i have them running at around 10ma. My thought was an i think i'm wrong now was that at that currant there would be no heating and no thermal runaway.

How else could i power them?

funkyguy4000:
Interesting....
When I connect up the 2nd led in the backwards direction with the resistor going to GND. the whole circuit turns off. I thought that those two resistors might just be shorting out the whole circuit.

Is that whats going on?

If you moved the top 220R resistor to go to Gnd, then there is no power reaching pins 2 and 6.