SFH6286 Optocoupler

[rtstorm]

Hi, please help me. I need to test this optocoupler but i am not sure if it is OK or not.

I test diode test and got readings:

between 1 and 2 = 0
between 2 and 1 = 0

between 3 and 4 = 1.28V
between 4 and 3 = 1.28V

shoud i have reading between 3 & 4? Resistance between 3 & 4 is 25 Mohm

here is schematic

[multimeter]

Re: SFH6286 Optocoupler

Hi, please help me. I need to test this optocoupler but i am not sure if it is OK or not.

I test diode test and got readings:

between 1 and 2 = 0
between 2 and 1 = 0

between 3 and 4 = 1.28V
between 4 and 3 = 1.28V

shoud i have reading between 3 & 4? Resistance between 3 & 4 is 25 Mohm

here is schematic

that opto is shot,the diode led should have reading one way and not the other

in my exp the led blows 1st.

[tom66]

Re: SFH6286 Optocoupler

There are two matched LEDs in that device, in inverse parallel, so reading both ways is OK.

[selldoor]

Re: SFH6286 Optocoupler

That was my immediate thought but when you look at the picture it has two
diodes ? so does that cancel the test out?
Most diagrams for Optoisolators have only one diode?

Ha - Thanks Tom beat me to it while I tried to spell optoisolator tho I wasnt sure.

What about part two - reading between 3 & 4 - voltage reading?

[rtstorm]

Re: SFH6286 Optocoupler

it have 2 diodes on one side (1 and 2) i have reading in both way on other side (3 and 4)

[rtstorm]

Re: SFH6286 Optocoupler

i think part one (1 and 2) is ok, but second is i think bad. Should i have both reading between 3 and 4?

[selldoor]

Re: SFH6286 Optocoupler

If I remember correctly it is difficult to test that 3/4 side. Look it up on google I think you need 2 analogue voltmeters. But you can test for a voltage on the board.

[budm]

Re: SFH6286 Optocoupler

"3 & 4 is 25 Mohm" that is just the Emitter-Collector leakage resistance.
"between 1 and 2 = 0
between 2 and 1 = 0"
Do you mean 0 on you meter in Diode mode? It should show 1.1~1.5 (per spec of the Opto) reading. Note: in diode mode testing, the meter is actually showing the Vf (forward voltage) of the device.
You can use 3V battery with 470 Ohms resistor in series to limit the current and connect it to pin 1 and 2, polarity does not matter since this is an AC input Opto (it does not care about the polarity of the input voltage due to dual LED inside). On the output side you can set your meter to 200 Ohms or 2K or in continuity mode (this will depend on the meter spec), you should see low resistance when the battery is connected to 1 & 2 with that resistor in series.

[rtstorm]

Re: SFH6286 Optocoupler

"3 & 4 is 25 Mohm" that is just the Emitter-Collector leakage resistance.
"between 1 and 2 = 0
between 2 and 1 = 0"
Do you mean 0 on you meter in Diode mode? It should show 1.5~1.8 reading. Note: in diode mode testing, the meter is actually showing the Vf (forward voltage) of the device.

I mean 0 like no connection, yes 0 in diode mode.

[budm]

Re: SFH6286 Optocoupler

No, it should not show no connection, get 2 red LEDs and connect them back to back just as shown and test with your meter, that is about the reading it should show.


They are just 2 LEDs back to back inside.

[rtstorm]

Re: SFH6286 Optocoupler

"3 & 4 is 25 Mohm" that is just the Emitter-Collector leakage resistance.
"between 1 and 2 = 0
between 2 and 1 = 0"
Do you mean 0 on you meter in Diode mode? It should show 1.1~1.5 (per spec of the Opto) reading. Note: in diode mode testing, the meter is actually showing the Vf (forward voltage) of the device.
You can use 3V battery with 470 Ohms resistor in series to limit the current and connect it to pin 1 and 2, polarity does not matter since this is an AC input Opto (it does not care about the polarity of the input voltage due to dual LED inside). On the output side you can set your meter to 200 Ohms or 2K or in continuity mode (this will depend on the meter spec), you should see low resistance when the battery is connected to 1 & 2 with that resistor in series.

i try this, and i do not have low resistance on output. So can we confirm that this optocoupler is bad?

[budm]

Re: SFH6286 Optocoupler

I think it is bad due to 0 reading on pin 1 and 2 as you reported so the Phototransistor inside does not detect anything from the LEDs.