4N35 vs H11G1 Opto's

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#1
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Hi Guyzz

I have two types of Optocouplers here at home

1: http://www.ortodoxism.ro/datashe...

2: http://www.fairchildsemi.com/ds/...

Until now i have only used the 4N35 , as i can not really understand the "advantage"/force of the H11G1.

Where would i use the H11G1 ???

As i undestand it : It is temperature stable due to the build in resistor , and i think i can see that you can drive 150ma continuous with it.
That CTR they talk about is that the "hfe" ???

Any hints or explanations would be appreciated , i have around 100 of each , and would like to use them :-)

Edit: Added the correct 4N35 ds URL

/Bingo

Last Edited: Mon. Jun 13, 2005 - 03:54 PM
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Ohh They are named QTC H11G1
So i guess they are QTC ones
http://www.ortodoxism.ro/datashe...

/Bingo

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Three or four important differences:

The 4N35 turns off a lot faster. (2uS vs 100)
The 4N35 has a much better "low" output. (0.3V vs 1.0)
The 4N35 has a much lower "dark current".
The H11Gx output stage is rated for a higher voltage.

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The H11G has a Darlington output. This means more gain but higher saturation voltage and slower switching speed. Higher gain probably means that the LED can be run at a lot lower current.

It also appears that the rated output breakdown voltage is higher though that is not a function of the Darlington connection.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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The H11G has a current transfer ratio of 1000% (e.g. current gain of 10); the 4N35 is 100%..

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Thanks Guyzz

So i guess , for normal use the 4N35 is really the best choise.

The H11G is for "picking up" a signal without loading it (the led uses less current or ??) , and the H11G can drive a higher voltage on the output , but reacts a lot slower when turning off.

For AVR use i guess the "low" 1v output would not be important , but what about a HCTxxx (Well i can look that up).

/Bingo