I bought one Ir-transmitter and one Ir-receiver. The transmitter likes a LED but with transparent window and has two pins. The receiver likes a n-p-n or p-n-p transistor and has three pins. How can I identify their operation voltages and other specifications? No information available in this stupid shop! What can I do? Throw them away? Or test them under 5V with protective resistor? Hi, All the experts here, please help me!