Sorry man , but I do not know how to generate a pulse !<br>What signal source do I use ?<br>I have no practical experience in electronics<br><br>Regards,<br>Deepak<br><br><div><span class="gmail_quote">On 21/03/2008, <b class="gmail_sendername">Arun Krishnan</b> <<a href="mailto:arunk@speedpost.net">arunk@speedpost.net</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Deepak,<br> <br> I don't think a 555 can clock to the 10Mhz you'll need to test your LED<br> at.<br> <br> But I'm thinking you can measure the rise and fall time just by a single<br> pulse and a CRO that has enough resolution.<br>
<br><br> Regards,<br> Arun<br> <br> <br> ----- Original message -----<br> From: "Deepak Mishra" <<a href="mailto:xask.linus@gmail.com">xask.linus@gmail.com</a>><br> To: "Twibright Ronja" <<a href="mailto:ronja@lists.pointless.net">ronja@lists.pointless.net</a>><br>
<br>Date: Fri, 21 Mar 2008 20:00:19 +0530<br> Subject: Re: [Ronja] Testing switching time of an LED<br> <br> Thanks ,<br> I had this basic idea in mind that I must apply a fast input square wave<br> signal to the led and check the output using a scope on the photo diode.<br>
<br> But the basic problem is I am such a new bie that I am not sure if i<br> should<br> connect<br> the photo diode directly to the oscilloscope and with resistor in series<br> or<br> what ??<br> <br> And how do i generate a square wave signal of the desired frequency ?<br>
I have heard of the 555 timer, do I have to use the breadboard ?<br> <br> I good with software, but not so good at hard ware, I hope you get the<br> idea<br> ?<br> <br> Thanks anyway!<br> Cheers,<br> Deepak<br> <br> <br>
On 21/03/2008, Arun Krishnan <<a href="mailto:arunk@speedpost.net">arunk@speedpost.net</a>> wrote:<br> ><br> > Hi Deepak,<br> ><br> > You'll need to hook up the LED to a simple square wave generator and use<br>
> a fast photodiode connected to a CRO to measure how fast it is<br> > switching. There are other methods where you could program something<br> > like a microcontroller to measure it, but the easier way would be to use<br>
> a CRO.<br> ><br> > Regards,<br> > Arun<br> ><br> ><br> ><br> > ----- Original message -----<br> > From: "Deepak Mishra" <<a href="mailto:xask.linus@gmail.com">xask.linus@gmail.com</a>><br>
> To: "Twibright Ronja" <<a href="mailto:ronja@lists.pointless.net">ronja@lists.pointless.net</a>><br> > Date: Fri, 21 Mar 2008 19:13:44 +0530<br> > Subject: [Ronja] Testing switching time of an LED<br>
><br> > Hi all !,<br> ><br> > As always, I am having trouble find the LED HPWT-xxxx-xxxx.<br> > So I am going to test some LED manufactured in my country (India) easily<br> > available at low costs.<br>
><br> > I mainly want to test the rise/fall time of the LED and its not in the<br> > datasheet.<br> ><br> > I am an electronics newbie, so could somebody point me to an electronic<br> > circuit and a way to measure<br>
> the rise and fall times of the LED ?<br> ><br> > Cheers,<br> > Deepak<br> ><br> ><br> > --<br> > Twibright Ronja mailing list <a href="http://ronja.twibright.com">http://ronja.twibright.com</a><br>
> <a href="mailto:Ronja@lists.pointless.net">Ronja@lists.pointless.net</a><br> > <a href="http://pointless.net/mailman/listinfo/ronja">http://pointless.net/mailman/listinfo/ronja</a><br> ><br> <br> <br>--<br> <br>
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