Diodes Exp.2

First I had to identify which is the cathode (negative) and which is the anode (positive) on both Diodes and L.E.D's without using a multimeter..

To determine which is which on a diode, you can look up to the diode and see the one side which has a white strip, this is the cathode therefore the other side without anything just plain black is the anode.

To determine which is which on a L.E.D, look at the legs on the bottom of the L.E.D and you will see there is a longer leg and a shorter one, the longer one representing the anode and the shorter one representing the cathode or there is also a flat side on the bottom circle ring of the light which represents the cathode also..

Objective..

Next had to build a circuit board with a 5V power supply a 1k resistor and a 1N4007 diode on a breadboard.

First had to calculate the amount of current(amps) flowing through the the diode and then measure it with my multimeter to get an actual reading.

Results..

Calculation: 5V - 0.7V = 4.3V

4.3V/1000 ohm's = 0.0043a

or = 4.3ma

Measurement with multimeter:

= 4.5ma

I found that the Actual measurement was .2ma higher then my original calculations, maybe because resistance in the wires or not quite a perfect contact with the multimeter etc..

Objective..

Next had to calculate and measure the voltage drop across the diode on the same breadboard with the 5V power supply a 1k resistor and the 1N4007 diode.

Calculation: 4.3ma/1000 ohm's =4.3v

5v- 4.3v = 0.7v

Therefore voltage drop should be somewhere close to 0.7volts.

Measurement using a multimeter: 0.666v

This experiment worked out well and calculation to measurement was only slighty off to compare. (Picture up top left of me measuring circuit board with my multimeter for voltage drop).

Objective..

Next,had to replace the diode with a L.E.D(light emitting diode) and calculate then measure the circuit with my multimeter.

1.7v being the amount of power used to power the L.E.D..

Calculation: 5v-1.7v = 3.3v

3.3v/1000 ohm's = .33ma

Measurement using multimeter: .5ma