flashing Railroad LED's

[sammy004]

Hi guys I put this circuit together and it works good until you add more then 9 volts to it then one of the leds just kind of dims down while the other just flashes like regular. So at 9volts it flashes side to side but at 12 volts it still flashes but one of the leds just dims downs I am using 500ohm res. with the led's everything else is the same. Can anyone tell me what might be wrong I was thinking that I just have a resistor the wrong value somewhere.

 

[Reloadron]

What circuit? I am not seeing any attached file or link?

Ron

 

[sammy004]

What circuit? I am not seeing any attached file or link?

Ron

Oh mybad I'm sorry..
here it is FLASHING RAILROAD LIGHTS Circuit

 

[bychon]

Exactly which 555? The old style needs a capacitor to ground on pin 5.

 

[sammy004]

What do you mean? Do you mean which one I have?

 

[bychon]

No, the one you left at the store.

 

[Reloadron]

The circuit you linked to I am not sure about. Looks like they have the 555 pin 3 output tied back to your RC timing network for the 555? Take a look at this similar circuit.

My best guess is the circuit you have was incorrectly drawn for the web. Tie the side of your 47K resistor not going to pins 6 & 2 to your power like shown in my link. That should get it working.

Also, per Bychon you may want to place a .01 uF between pin 5 and ground but I would change the other first.

Ron

 

[MikeMl]

The Op's circuit should work as drawn, with the exception of the missing bypass capacitor on pin5.

 

[Reloadron]

Then per the simulation Mike was nice enough to provide I would just add the bypass cap on pin 5.

Ron

 

[sammy004]

Thanks guys for your help I will try that and as for bychon I have no clue what your talking about, I didn't buy anything at the store.

 

[bychon]

Which 555 do you think we're talking about here?

The one you have or the one you don't have?

 

[sammy004]

Which 555 do you think we're talking about here?

The one you have or the one you don't have?

Well yeah obviously but when you said "Exactly which 555?" well which one do YOU think i'm working with

 

[Mikebits]

Well yeah obviously but when you said "Exactly which 555?" well which one do YOU think i'm working with

This portion of the conversation reminds me of a clip from Analyze this. Fast forward to 6.00 min to see what I mean
YouTube - Analyze This Ending, "Meeting with The Bosses"

 

[bychon]

Another first for me. A guy who actually challenges us to guess which chip he's talking about!**broken link removed**

 

[Mikebits]

Another first for me. A guy who actually challenges us to guess which chip he's talking about!**broken link removed**

Maybe he is not aware that there is more than one flavor of the 555 chip, in which case he might be wondering WTH your talking about. Just a thought.

 

[bychon]

Well, I'm guessing that it is either an NE, SE, CSS, Av, XR, HA, ICL, ICM, MC, LM, LMC, RM, SN, TLC, or ZSCT prefix.

 

[sammy004]

Well, I'm guessing that it is either an NE, SE, CSS, Av, XR, HA, ICL, ICM, MC, LM, LMC, RM, SN, TLC, or ZSCT prefix.

Yeah smart guy. I don't know as much as you so it would be nice to explain to people in detail. The other people explained it to me with clarity and now my project works nice so the mods can close this f they want.

 

[sammy004]

Maybe he is not aware that there is more than one flavor of the 555 chip, in which case he might be wondering WTH your talking about. Just a thought.

I really thought there was only one kind of 555.

 

[angie1199]

I really thought there was only one kind of 555.

So did I

This has the appearance of one of those books you buy when you get three pages in and suddenly the author expects you to know what they're talking about, but you actually bought the book to learn what they're talking about

 

[bychon]

Glad I could help with that"capacitor on pin 5 suggestion". You're welcome.