Infrared Emitting Diode and Silicon NPN Phototransistor

I have connected the infrared emitting diode with a 2 v supply and the phototransistor with a 5v supply. My objective is to find out the difference when the infrared emitting diode is on and off. Until now I could not find any effects on the photo transistors using multimeter to test for the current and voltage.

Any help or info would be appreciated.

Put them both on 5v. What load resistor are you using?

Do you have a resistor in series with the diode to establish the diode current? If not you may have blown the diode.

There is no diode. The IR LED is blown up.