HW 9 Name v3 SP19 Sec. 1 a) What is an LED and how does it differ from a rectifier diode? b) What is the typical voltage drop across a display LED? c) What is a typical current for a display LED? d) Is the LED a polarity sensitive device? If it doesn't light what is the 1st thing that should be done? 2. a) When light enters a Photo Transistor what is Vc? b) When there is no light what is Vc? c) Explain how LED/Photo Transistor works. OPB732 d) What is advantage of using LED/Photo Transistor vs just Photo Transistor to detect RC car? Photo- transistor/LED