i was wondering if someone could help me on this matter,i made a ir transmitter and it is working,but i have know idea how the reciever works,all i want to do is light up an LED when the transmitter is on,and turn it off when the transmitter is off. the receiver is a infrared phototransistor with 2 prongs, anode ,cathode any help would be great THANKS....

 

Connect the photodiode cathode in series with a resistor (say 10K for starters) and connect the whole lot accross a supply (say 5V) with the resistor to positive.
Use a comparator (or op-amp connected as a comparator) with its + input connected to the photodiode/resistor junction.
Bias the - input to say 1V using a couple of resistors accross the supply.

Connect the LED to 0V and the comparator output with a series resistor (about 150R for 5V supply).

you might have to adjust the bias resistors and/or the 10K resistor to get required sensitivity.

 

thanks for that it works great, much appreciated