Generate pused frequensies with LED's

[jesperbrannmark]

Hello everyone.

I just managed to connect a LED to battery source.
I've used a 40mA 1.7V 660nm LED (pretty strong) with a 3V
battery source and a resistor as described in this forum.

Now for the next step:
I want to make this a pulsed light, and as I recall here is where
the condensator comes to work.

If I want the LED to have a blink frequency of 146 hZ (+-10% something like that), what kind of condensator and what sort (ceramic, electrolyte ...?)

And how will i do to use a 4672 hZ pulse instead?

Will this effect the power output (or the light candela) of my led?

For anyone wondering about the strange pulses and nm colors i use,
this is a analgestic frequency often used in physiotherapy.

Jesper Brännmark, DC student

 

[David Bridgen]

In order to pulse the l.e.d. you will need an oscillator using a couple of transistors or an i.c., you can't do it by just adding a capacitor.

The light intensity is proportional to the current through the l.e.d.
If you pulse it with a 50% duty cycle the average light intensity will be 50% of the steady-state value.

 

[chemelec]

You could try this circuit on my Website.

**broken link removed**

 

[David Bridgen]

Nice one Gary.

 

[jesperbrannmark]

You could try this circuit on my Website.

**broken link removed**

I had a look at it, and seem to get the basic of it.
Really nice of you to answer so fast! Lovely!

Just two questions.
Something described as 2N5964 looks like a diod.
Anod, katod i'm familiar with. G should be ground?
What diod is this? Search of the number on yahoo gives me a component
made by Fairchild, and i cant seem to find any data about it?
The second question, is there any smart way to calculcate the hZ of the pulses?

 

[ljcox]

It would be simpler and better to use an IC such as the 555.

If you search this forum for 555, you will find plenty.

The "diode" in the posted circuit is a SCR.

Len