On 9/4/06, Mario Mendes <mario@mmendes.com> wrote:
> Does anyone know what is the typical output impedance of a laptop's
> headphone jack?  The only usefull info I have found is that the majority
> of these jacks will put out 1v rms.  Also, not being knowledgeable in
> analog electronics (I do fine in with digital electronics though), can
> anyone help me out with coming up with an opamp circuit that would take
> care of this impedance matching?  Since this is for home use, I thought
> that a couple of opamps (1 left and 1 right) could take care of it with
> either a 9v battery or a simple power supply.  This would plug into the
> pc headphone jack and the fm transmitter would plug into it.

I seem to recall that most headphones are around 32 Ohms impedance. I
can't remember where I read that though, and that's sort of assuming
that the laptop manufacturers are actually designing for average
headphones.

Josh
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