[sdiy] MIDI Optocoupler

[Tim Parkhurst]

Hi All,
 Just came across a whole bunch (like 2000) of a Philips 4N35 optocoupler.
I've seen these listed in some Sound Blaster to MIDI schematics, so it looks
like they're okay for use in MIDI applications. What I'd like to know is,
what is really the determining characteristic for a MIDI optocoupler? Speed?
The 4N35 has a switching speed of about 3uS, so (1/.000003)/2 = a maximum
switching speed of approx. 167kHz right? (divide by 2 because each cycle is
two transitions, and 1/3uS to get frequency... right?) Anyway, if this is
correct, then this part should be more than fast enough for MIDI. What about
current capability? Any other factors to look at when picking an
optocoupler?
 By the way, if these things are good for MIDI, I'll sell 'em real cheap
since I have so darn many (something like $2 + shipping for a tube of
twenty, I have to see how many are in a tube).
Tim (right?) Servo
--
"Imagination is more important than knowledge." - Albert Einstein
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