help with IR detector

i bought a couple of IR emitter detector pairs for my line follower project.
i was told that they were a pair of matched TIL31 TIL81 emitter sensors.

on checking the datasheet i found that the detector is supposed to have 3 pins whereas mine has only two.
the IR emitter works fine but there is no change in the sensor whatsoever .
neither potential that is developed or change in resistance ..

i am implementing the attached circuit but it does not work as it is supposed to.
help.

The circuit is pretty simple; if it does not function, then you probably have
something mis-connected. Check your emitter/collector connections.
Check the collector voltage with and without a light source - that will tell
you if the detector is good and wired properly.
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