Thursday, July 22, 2010

Experiment 2



---------------------Voltage drop in forward -------------Voltage drop in reverse
LED-----------------1.761 volts---------------------------0 volts
DIODE--------------0.541 volts---------------------------0 volts

LED cathode side got shorter wire and flat side, and diode cathode side marked with grey stripe.



R=1000 ohm __________ V=5.31 v _________ Vd=0.657v

Calculated amps____________________________Measured

5.31-0.657=4.653___________________________4.6 mili amps

I=4.653/1000=4.653 mili amps


Its a voltage drop of 0.657 volts at diode as it use this voltage to run.


Calculated voltage drop--------------------------Measured voltage drop


Va=5.31-----------------------------------------0.664 volts


I=4.653 ma


R=1000 ohm


V=IxR=4.563*1000=4.563 volts


Vd=Va-V=5.31-4.653=0.657 volts

Max value of current that can flow through diode


1 amp at 75 C degrees


For R=1000 ohms, what is max Vs


Vs=1amp*1000ohms=1000 volts


Now diode replaced with LED



Calculated current amps-----------------------------Mesured current amps


Vs=5.31 volts----------------------------------------3.3 mili amps


Vd=1.967


V=Vs-Vd=3.343

I=V/R=3.343/1000=3.343 mili amps


LED light voltage drop was hiher then diode, and as it takes more voltage to run, then less amps flow through LED.

1 comment:

  1. nice use of photo to help explain what you are doing

    ReplyDelete