Experiment No.2 - Diodes

In this experiment we where given two types of diodes, one a rectifer diode and the other a LED, we had to identify the anode and cathode of these two diodes using a multimeter.

The cathode end of the recifier diode is shown by a silver strip going around the end of it.

The cathode end of the LED is shown by the shorter leg which is the cathode or a flat spot on the LED next to the cathode end.

Next I had to caculate the value of current flowing through the diode in a circuit. I made this circuit using a 5v input, a 1kohm resistor and a 1N4007 diode on a breadboard.

Caculated current flow

5v - .7 = 4.3mA

I = 4.3/1 = 4.3mA

Measured

4.7mA

This reading is a little higher than i thought it would have been, but there is not much difference between the two.

The maximum value of the current that can flow through the diode is 1A.

For the 1kohm resistor the maximum value of V's so the diode operates in asafe region is 1000vs.

Next I replaced the diode with the LED and caculated the current.

Caculated current flow

5v - 1.94 = 3.06

I = 3.06/1 = 3.06ma

Measured

3mA

I observed that the LED uses more voltage (voltage drop) than the diode, this is because the LED needs voltage to light up.