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Topic: high frequency optoisolator needed (Read 547 times) previous topic - next topic

Rusk

here I am trying to design an analog project which counts the frequency.Circuit consist of an photo transistor optoisolator and some counters for counting number of cycles per second.For this 1 second i am using timer ic(555).Now my doubt is which is the best phototransistor opto isolator should I use inorder to count frequency till 16 Khz.As above 16Khz i would require prescalar.
Thanking you in advance



Magician

With 16 kHz I think any 4N25 - 38 would be o'k.  6N136 guaranteed up to 1Mb, and 6N137 to 10 Mb, though price is also goes up.

Rusk

#2
Feb 01, 2013, 07:36 pm Last Edit: Feb 01, 2013, 07:38 pm by Rusk Reason: 1
Are you sure sir?
Will 4N25 take 16Khz on itself?
Is there any extra hardware required ?

Magician

Not sure, my guess is based on 2 usec rise and fall time in data sheet, 16 kHz = 66 usec, it appears there is x30 times difference between

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