Simulation has been a part of circuit design ever since. It is done before creating the actual circuit design because it is less expensive and time-efficient. Technological advancements have led to the invention of different tools and software used in simulating circuit designs. One of the most popular and widely used simulation software is the LTSpice. In this laboratory experiment, the students will familiarize themselves with the basic SPICE directives and commands. The students are also going to calculate for the values of the variables in the parameters used in LTSpice and compare it to the plot to determine the behavior of the circuit. Then, the students will simulate circuit designs with the use of SPICE directives and then compare it to the calculated values. The students are also going to identify the advantages and disadvantages of using LTSpice in circuit design. Overall, the students will familiarize and merge their obtained skills and knowledge with LTSpice in simulating and designing their own circuit.Before creating an electronic device or circuit, simulation always comes first to identify the outcome of a created design through the use of mathematical models. And because of technological advancements, different software have been made and used in the simulation of electronic devices and circuits. One of the most popular and widely used software in designing and simulating electronic circuits is the LTSpice. LTSpice is a free-for-all computer software which utilizes SPICE (Simulation Program with Integrated Circuit Emphasis) in designing and simulating electronic devices and circuits. It is a useful tool because it gives you guidelines on how your circuit design will work. It can also serve as a tool for visualizing your desired circuit design before actually creating it. And in LTSpice, the learning and testing a circuit will be more convenient because of its feature that allows you to examine the waveforms on different parts of the circuit. In line with this, the students have familiarized themselves with the basic SPICE directives used in this laboratory experiment.
In the first activity, a basic voltage divider was simulated. The .param command used designates the value of the resistor. The .step param command used creates a step function which varies from 1k to 10k with a step of 2.25k. The .tran command calculates the non-linear algebraic-differential equations of the voltage divider circuit with a stop time of 10 seconds. Then, in the second activity, we simulated a linear voltage regulator, namely the LT317A using the DC sweep function. The .dc command calculates the DC analysis of the voltage regulator circuit and increasing or decreasing the applied voltage. In the third activity, we simulated a second-order band-pass filter. The .ac command used calculates the small signal analysis of the filter linearized throughout its DC operating point. And in the fourth activity, we simulated an ideal operational amplifier using the transient analysis. The transient analysis calculates the non-linear algebraic-differential equations of the operational amplifier with a stop time of 100 milliseconds. The .param command gives the resistors a fixed value. While in the fifth activity, we simulated a pulse signal using the pulse function from the voltage source. The signal created is similar to the signal used in the input/output ports of an Arduino microcontroller. The .tran command calculates the non-linear algebraic-differential equations of the voltage divider circuit with a stop time of 40 milliseconds. Lastly, in the sixth activity, we simulated a full bridge rectifier using the step parameter. It has an input voltage of 120 Vpk-pk and a frequency of 60 Hz to be converted to a 120V pulsating DC. The step parameter displays the essence of using different capacitors as a filter, namely 10 uF, 90 uF, and 100 uF capacitors.Upon performing the laboratory
experiment, the students calculated for the values of variables used in the simulation.
These calculations will be used to support the fulfillment of laboratory
experiment. The following calculations were made to compare the simulated and
calculated values later in the laboratory experiment.