Looking for 555 help

[Fett2303]

I'm looking for help with a wiring diagram for two LEDs to flash. I want them to alternating between the two (1 led will flash and when it goes off other flashes) using 555 timer.

 

[TiM]

http://www.555-timer-circuits.com/flashing-railroad-lights.html

For example...?

one way to do it ;D

 

[Grendels]

That looks like it should do the trick!

 

[Fett2303]

The resistors slow down the timing?

 

[Grendels]

Only the 47K resistor is for timing, the other resistors are for keeping the LED from burning out. With the 555 timer chip, the supplied voltage is the voltage that the chip puts out. So if you are supplying 12V like this circuit does, you need the 470K resistor to keep from burn outs. You can adjust the 470K resistor for the voltage you are supplying.

 

[TiM]

If your output from the chip is directly connected to an LED, you are delivering 2/3 of the rail voltage as the internal resistors act as a voltage divider within the chip. So for example, a 555 timer directly supplying a "high" output state to an LED from a 9V supply is giving 6V to the LED line without resistor to drop it. dead led btw...

currently looking for the link where I read it all... I'm a materials engineer not electronics, ;D

 

[Grendels]

If your output from the chip is directly connected to an LED, you are delivering 2/3 of the rail voltage as the internal resistors act as a voltage divider within the chip. So for example, a 555 timer directly supplying a "high" output state to an LED from a 9V supply is giving 6V to the LED line without resistor to drop it. dead led btw...

currently looking for the link where I read it all... I'm a materials engineer not electronics, ;D

Funny, when I read up on the 555, the information I found about it told me that input voltage was equal to output voltage. Almost every circuit design I have ever seen does this. What you posted does make sense, the 555 has to get it's power from somewhere....

I will probably keep on with the in=out. Just a built in factor of safety.

 

[TiM]

You're right, I'm wrong.... the 2/3 is the voltage across the timing Capacitor required to flip the output... the output voltage is switched by transistors to deliver Vcc. :-[

 

[Grendels]

Good to know!

 

[Chiver]

i would love to start using 555 chips, but this is way to confusing for me. i'm new to lighing, and i'm planming a few light build. and for cost sake i would liek to buy and build my own circurts. my first will be a romulan warbird lit up with FO. and no strobe,

 

[Grendels]

There is a lighting tutorial at the top of this section. I have videos up on the basics for LED's and how to use them. Different types of LED's, two different timing circuits etc.

Try watching the videos, if they don't help, then come back and post questions. We will answer them.