[Ronja] Testing switching time of an LED

[Deepak Mishra]

Sorry man , but I do not know how to generate a pulse !
What signal source do I use ?
I have no practical experience in electronics

Regards,
Deepak

On 21/03/2008, Arun Krishnan <arunk at speedpost.net> wrote:
>
> Hi Deepak,
>
> I don't think a 555 can clock to the 10Mhz you'll need to test your LED
> at.
>
> But I'm thinking you can measure the rise and fall time just by a single
> pulse and a CRO that has enough resolution.
>
>
> Regards,
> Arun
>
>
> ----- Original message -----
> From: "Deepak Mishra" <xask.linus at gmail.com>
> To: "Twibright Ronja" <ronja at lists.pointless.net>
>
> Date: Fri, 21 Mar 2008 20:00:19 +0530
> Subject: Re: [Ronja] Testing switching time of an LED
>
> Thanks ,
> I had this basic idea in mind that I must apply a fast input square wave
> signal to the led and check the output using a scope on the photo diode.
>
> But the basic problem is I am such a new bie that I am not sure if i
> should
> connect
> the photo diode directly to the oscilloscope and with resistor in series
> or
> what ??
>
> And how do i generate a square wave signal of the desired frequency ?
> I have heard of the 555 timer, do I have to use the breadboard ?
>
> I good with software, but not so good at hard ware, I hope you get the
> idea
> ?
>
> Thanks anyway!
> Cheers,
> Deepak
>
>
> On 21/03/2008, Arun Krishnan <arunk at speedpost.net> wrote:
> >
> > Hi Deepak,
> >
> > You'll need to hook up the LED to a simple square wave generator and use
> > a fast photodiode connected to a CRO to measure how fast it is
> > switching. There are other methods where you could program something
> > like a microcontroller to measure it, but the easier way would be to use
> > a CRO.
> >
> > Regards,
> > Arun
> >
> >
> >
> > ----- Original message -----
> > From: "Deepak Mishra" <xask.linus at gmail.com>
> > To: "Twibright Ronja" <ronja at lists.pointless.net>
> > Date: Fri, 21 Mar 2008 19:13:44 +0530
> > Subject: [Ronja] Testing switching time of an LED
> >
> > Hi all !,
> >
> > As always, I am having trouble find the LED HPWT-xxxx-xxxx.
> > So I am going to test some LED manufactured in my country (India) easily
> > available at low costs.
> >
> > I mainly want to test the rise/fall time of the LED and its not in the
> > datasheet.
> >
> > I am an electronics newbie, so could somebody point me to an electronic
> > circuit and a way to measure
> > the rise and fall times of the LED ?
> >
> > Cheers,
> > Deepak
> >
> >
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> >
>
>
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>
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