what opto-isolator do i need?

I want to order from this site: http://nl.rs-online.com/web/c/?searchTerm=OPTO+ISOLATOR&sort-by=P_breakPrice1&sort-order=asc&view-type=List&sort-option=Prijs

but there are like 232 search result...

I want to use it for this: http://www.glacialwanderer.com/hobbyrobotics/?p=10 (flash triggers by a 5v signal).

What specs do i need? (i need one with a total of 4 pins)

also if someone can find a powerswitch tail on http://nl.rs-online.com then that would be great, they have 500.000 product and i can't find shit.

First, read the specifications of the optoisolator specified:


Then find one with similar specifications. The DigiKey catalog doesn't have any that aren't made by CEL so you might want to find a cupplier that caries CEL.

The example optocoupler is being driven pretty hard with that 50ohm resistor. But it is with the specs.

Any of the optocouplers here will probably work: http://nl.rs-online.com/web/c/optoelectronics-displays/optoelectronics/optocoupler/?searchTerm=OPTO+ISOLATOR&sort-by=default&sort-order=default&applied-dimensions=4294886486,%204294883459,4294884274&lastAttributeSelectedBlock=Pin%20Count