Flashing LED

[George]

Hi Guys
What is the recommended capacitor for this circuit?


I want to use it to simulate an arc welder in an engine shed on a model layout.
Thanks

That all depends on the frequency you want. Increasing the capacitance will decrease the frequency so decreasing the capacitance will increase frequency. Changing R1 and R2 will alter the high and low time also. Here is a good online calculator for this.

http://www.ohmslawcalculator.com/555-astable-calculator

Sorry for such a late reply but I have not been around for a long time now.

 

[scuboo]

I was hoping to simulate the flashing of an arc welder, so with a bright white led flashing fast enough to look like that. I have heard using the same circuit but adding another 555 chip in so it acts as a timer to stop it for a certain amount of time. I'm unsure tho.

 

[George]

I was hoping to simulate the flashing of an arc welder, so with a bright white led flashing fast enough to look like that. I have heard using the same circuit but adding another 555 chip in so it acts as a timer to stop it for a certain amount of time. I'm unsure tho.

I don't have the time tonight but will show you with a video and write up tomorrow. Sorry I worked a 12 hour overnight shift last night and need to get some sleep tonight. Check in around noon or so.

 

[George]

I was hoping to simulate the flashing of an arc welder, so with a bright white led flashing fast enough to look like that. I have heard using the same circuit but adding another 555 chip in so it acts as a timer to stop it for a certain amount of time. I'm unsure tho.

Real quick, we can just use 1 555 wired as Monostable to control the time the other 555 is flashing the led, that will allow you to set time like you want. The one that is flashing will be wires as Astable which gives you the frequency you want, fast/slow, to flash the led. How long do you want it on?

 

[scuboo]

Thank you very much. I guess I only want it on for a split second, just so it flashes really fast, like that for maybe 30seconds to 1 min and off for 30 seconds to a min. Once I get the circuit in place I'll be able to change resistance and capacitors, I'm just unsure of it. I really appreciate the help. It's been 15 years since I've done anything in electronics