Procedure

For “Low frequency switching device (SCR)”

1. 'v-i' Characteristics using meters:

a) Click on ‘Connections’ icon. A table containing all will terminals appear.

b) Click on each starting terminal and observe the corresponding connection.

c) After all nodes are connected, Click on ‘Connections Completed’ icon.

d) ‘Switch- ON’ the main supply (V_in).

e) Click on ‘Start Experiment’ icon.

On the Experiment page:

a) Observe the ‘v-i’ characteristics plotted on the graph on the right side. They are plotted for three different values of gate currents (Ig) by using the data logging features of the meters.

2. 'v-i' Characteristics using probes and oscilloscope:

a) Click on ‘Connections’ icon. A table containing all will terminals appear.

b) Click on each starting terminal and observe the corresponding connection.

c) After all nodes are connected, Click on ‘Connections Completed’ icon.

d) ‘Switch- ON’ the main supply (V_in).

e) Click on ‘Start Experiment’ icon.

On the Experiment page:

a) Click on the ‘R_g’ slider to set it at an initial maximum value of 25 kΩ. This sets the gate current (I_g) to zero. Click on the Resistance icon- ‘R’ to set the load.

b) Click on the ‘v_in’ slider to set the main supply voltage to 15 V (rms)

c) Click on the ‘plot’ icon. Observe the Reverse blocking and Forward blocking characteristics on the graph.

d) Click on the ‘R_g’ slider to set it to 750 Ω. Observe the gate current ‘I_g’. Click on the ‘plot’ icon. Observe the forward conduction characteristics of the SCR.

e) Repeat Step-4 for R_g = 150 Ω and 50 Ω.

For “Medium frequency switching device (IGBT)”

Output Characteristics using probes and oscilloscope:

a) Click on ‘Make connections’ icon.

b) A table listing all the terminals pops up. This a simple series circuit. Click on each ‘From’ terminal one after the other.

c) Observe the simultaneous connection being formed.

d) Once all the terminals are connected, click on ‘Connections Completed’ icon.

e) ‘Switch- ON’ the main supply.

f) ‘Switch- ON’ the Gate-to-Source supply.

g) Click on ‘Start Experiment’.

On the Experiment page:

a) Click on the Resistance icon- ‘R’ to set the load.

b) Set the initial Gate-to-Source voltage ‘V_GS’ using the slider.

c) Vary the Main voltage (V_in) using the “V_in” slider.

d) Click on ‘Plot’ to trace the characteristics.

e) Repeat Steps-2 to 4 for a total of five values of Gate-to-Source voltage (V_GE).

For “High frequency switching device (MOSFET)”

Output Characteristics using probes and oscilloscope:

a) Click on ‘Make connections’ icon.

b) A table listing all the terminals pops up. This a simple series circuit. Click on each ‘From’ terminal one after the other.

c) Observe the simultaneous connection being formed.

d) Once all the terminals are connected, click on ‘Connections Completed’ icon.

e) ‘Switch- ON’ the main supply.

f) ‘Switch- ON’ the Gate-to-Source supply.

g) Click on ‘Start Experiment’.

On the Experiment page:

a) Click on the Resistance icon- ‘R’ to set the load.

b) Set the initial Gate-to-Source voltage ‘V_GS’ using the slider.

c) Vary the Main voltage (V_in) using the “V_in” slider.

d) Click on ‘Plot’ to trace the characteristics.

e) Repeat Steps-2 to 4 for a total of five values of Gate-to-Source voltage (V_GS).