Practical exercises with LTSpice

Applications of semiconductor diodes

Exercise 1:

Investigate the behavior of a forward-biased silicon diode with a small signal applied. To do this, create the circuit shown in the figure below:

 

Then determine the value of the resistor at which the diode current will be equal to 1 mA. Enter the determined value as the resistance of the resistor R2 and then examine the waveform of the input and output signals on the oscilloscope. Based on the values of the pin-to-pin signals, determine the dynamic resistance of the diode. When you're done, compare the result with the video.


Exercise 2:

Create a simulation in which you include a two-wave rectifier in the Graetz circuit as shown in the figure below:


Examine the timing of the signal at the output of the power supply on an oscilloscope with the capacitor disconnected and the load resistor \( 1M \Omega \) that simulates a small load. Then add a capacitor \(100 \mu F\) and see how the output changes. In the last step, change the load resistor to \( 180 \Omega \) and compare the ripple after changing the resistor. When you're done, compare the result with the video below.


Exercise 3:

Investigate the current-voltage characteristics of the zener diode. To do this, create a circuit from the figure below in LTSpice:


When you're done, compare the result with the video.


Exercise 4:

Create a circuit from the following drawing in LTSpice:


Then examine how the ripple at the output will change after using the zener diode. When you're done, compare the result with the video.