EXPERIMENT2

Diodes

A diode has the characteristics of:

• An insulator when current tries to flow in one direction.

• A conductor when current flows in the other direction.

 

 

 

 

 

Exercise: Using a multimeter, identify the anode and cathode of the diode and the LED.

                                                                     LED                    Diode

Voltage drop in foward biased direction:        2.4v                  681mV

Voltage drop in reverse biased direction:       OL                      OL

Explain how you could identify the cathode without a multimeter:

The cathode end is marked with a white line and the short leg is for the LED.

                             Vs=5v, R=1k, D=1N4007

Calculate first the value of current flowing through the diode, now measure and check your answer.

Calculated: 5/1000= 0.005= 5mA Measured: 50mA

Calculate the voltage drop across the diode.
Calculated: 700mV Measured: 683mA


Replace the diode by an LED & calculate the current, then measure and check your answer.
Calculated: 1.8A Measured: 3.18mA