Hamamatsu 0805A dual optocoupler

[Smeero]

I'm building a Mu-tron III clone and just received an original dual optocoupler. I assume the cathode is the fat wire on the side with the white stripe but to be safe I tested for polarity.   I'm getting no reading either way testing the two wire side, so now I'm thinking I may have a dead part. Not real familiar with optocouplers, would I have to test the bottom leads in some conjunction with the top wires to confirm its kaput? What's the right way to test it?  Any help is appreciated.

[stecykmi]

first off, try and find a data sheet. or possibly one for a similar part.

if you can't find it, get a multimeter, set it to measure resistance, connect up two of the leads. then apply a small voltage to the other side ( i would try 2 - 3 volts just so nothing burns out) and you should see the resistance plummet. if not, try reversing the polarity of the voltage. if still nothing, try another combination of leads.

[Smeero]

first off, try and find a data sheet. or possibly one for a similar part.

if you can't find it, get a multimeter, set it to measure resistance, connect up two of the leads. then apply a small voltage to the other side ( i would try 2 - 3 volts just so nothing burns out) and you should see the resistance plummet. if not, try reversing the polarity of the voltage. if still nothing, try another combination of leads.

Thanks.Here's a little more on my predicament from the neutron filter layout...


Only the two leads are the same length (one is fatter than the other) and didn't test for polarity with each other on my Multimeter. Well I found the p873 data sheet and it cleared things up, it does follow convention with the white stripe. I still think it might be a dead part though



edit: nope its good tested  as follows
1. Connect a voltage source through a current limiting series resistor to the input.
2. Connect a pullup resistor to Vcc
3. See the output go low

[bpier]

I own the same 8005A for building a Neutron Filter ans I have the same problem : when I plug my digital multimeter on the lugs of the led of this opto, I obtain any result on the screen of my DMM. Is the white stripe indicate the cathode or the anode ? Regards. Pierre