# Help With OptoIsolator Specifications

M

#### Mike

Jan 1, 1970
0
Hi,

I'm trying to understand the specification of an NTE 3044
(http://www.nteinc.com/specs/3000to3099/pdf/nte3044.pdf). I'm think
I'm OK on the diode side in that it requires 1.15V to switch on and
the maximum forward voltage is 2V however I'm not at all clear on the
transistor side.

How can I figure out from the specs if I can hook the transistor up to
a 5V 4mA circuit? What I think I'm reading is that the breakdown
voltage is 80V.

Can someone help clarify this for me and may explain some of the terms
(dark current, V(BR)CEO etc.)

Mike

L

#### Lord Garth

Jan 1, 1970
0
Mike said:
Hi,

I'm trying to understand the specification of an NTE 3044
(http://www.nteinc.com/specs/3000to3099/pdf/nte3044.pdf). I'm think
I'm OK on the diode side in that it requires 1.15V to switch on and
the maximum forward voltage is 2V however I'm not at all clear on the
transistor side.

How can I figure out from the specs if I can hook the transistor up to
a 5V 4mA circuit? What I think I'm reading is that the breakdown
voltage is 80V.

Can someone help clarify this for me and may explain some of the terms
(dark current, V(BR)CEO etc.)

Dark current is the current that will leak through the transistor when the
LED is dark. Hey, nothings perfect in the real world!

Vbr is the break down voltage...this potential, when applied to the
transistor
will (likely) destructively pass regardless of the base.

Vceo is the voltage with the collector and emitter open circuited.

C

#### CFoley1064

Jan 1, 1970
0
Hi,
I'm trying to understand the specification of an NTE 3044
(http://www.nteinc.com/specs/3000to3099/pdf/nte3044.pdf). I'm think
I'm OK on the diode side in that it requires 1.15V to switch on and
the maximum forward voltage is 2V however I'm not at all clear on the
transistor side.

How can I figure out from the specs if I can hook the transistor up to
a 5V 4mA circuit? What I think I'm reading is that the breakdown
voltage is 80V.

Can someone help clarify this for me and may explain some of the terms
(dark current, V(BR)CEO etc.)

Mike

The NTE3044 is a cross for the H11G2, now manufactured by Fairchild and a
couple of other outfits. You might want to look at the datasheet to get more
complete specifications:

http://www.fairchildsemi.com/ds/H1/H11G2.pdf

If you're new to optocouplers, you might want to find an older Motorola
optocouplers databook. The General Applications section at the beginning is a
very good intro to the subject.

Good luck.
Chris

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