# Need help with circuit!

#### Raptor

Joined Nov 3, 2007
4
I am trying to make a small strobe project using an LED. I need the LED to flash at a fast rate (about 10 times per second). I can also use two or more LEDs instead of just one to get the same effect if that is possible. What is the easiest way of doing this? Thanks,
-Mike

#### lightingman

Joined Apr 19, 2007
374
Hi,Check out the ICL555/ICM555/NE555, or the CD4047. These are oscillator IC's, they will produce a square wave with a variable rate..Daniel.

Joined Feb 10, 2007
64
Blinking the led 10 times a second do you think it would be visible to see the blinking of led , either it will appear off or On , you need to assign a proper square wave with Greater (Ton) Ontime with 555 IC.

#### Ron H

Joined Apr 14, 2005
7,014
Blinking the led 10 times a second do you think it would be visible to see the blinking of led , either it will appear off or On , you need to assign a proper square wave with Greater (Ton) Ontime with 555 IC.
The Flicker Fusion Threshold is 16Hz, according to this site. If this is true, 10Hz would be visible.

#### Raptor

Joined Nov 3, 2007
4
It seems like the most common and easiest way is to use a 555 IC timer, but I forgot to mention I'm still a "beginner" at making circuits, so can someone tell me which components I need to buy and in which way I need to solder them together? Thanks,
-Mike

#### hgmjr

Joined Jan 28, 2005
9,027
Here is a post with an interesting flasher circuit attached.

You may what to consider it for your design.

Of course you will need to replace the incandescent lamp with a resistor in series with your LED. The value of the resistor will be based on the 10 or so volts output by the LM317.

hgmjr

#### Ron H

Joined Apr 14, 2005
7,014
Here is a post with an interesting flasher circuit attached.

You may what to consider it for your design.

Of course you will need to replace the incandescent lamp with a resistor in series with your LED. The value of the resistor will be based on the 10 or so volts output by the LM317.

hgmjr
I think that circuit wil eat LEDs unless you add some current limiting.

Joined Feb 10, 2007
64
Ron H i agree with you but there would just an illusion of blinking accn to PERSISTENCE OF VISION,isnt it ?

#### Ron H

Joined Apr 14, 2005
7,014
Ron H i agree with you but there would just an illusion of blinking accn to PERSISTENCE OF VISION,isnt it ?
When you look at a blinking light, and you perceive a blinking light, that's not an illusion.
Persistence of vision is what accounts for the flicker fusion threshold.

#### Raptor

Joined Nov 3, 2007
4
The percistence of vision and flicker fusion threshold is not necessarily important because it is an infared LED, since I am trying to replicate a "10 hz" signal for this project.

#### Ron H

Joined Apr 14, 2005
7,014
The percistence of vision and flicker fusion threshold is not necessarily important because it is an infared LED, since I am trying to replicate a "10 hz" signal for this project.
What are you really trying to do?

#### thingmaker3

Joined May 16, 2005
5,083
He's really trying to make an LED flash at a ten Hertz rate.

#### Ron H

Joined Apr 14, 2005
7,014
He's really trying to make an LED flash at a ten Hertz rate.
Well, after much studying, I figured that out.
It's just that I can't think of a stand-alone use for a 10Hz flashing IR LED. Some posters have an overall task they want to accomplish, and they zero in on what they think is a solution, but it turns out to be unworkable. Flashing an LED is a simple problem, so our OP may not be have much experience or knowledge about electronics. I'm not saying this is necessarily the case here, but we might save time and grief if we knew the overall problem.

PS the use of the term "replicate" is what set me off on this.

#### thingmaker3

Joined May 16, 2005
5,083
I just checked the first page of Google using "10Hz signal IR" (no quotes). Lots of possibilities.