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 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.