Beforecreating an electronic device or circuit, simulation always comes first toidentify the outcome of a created design through the use of mathematicalmodels.
And because of technologicaladvancements, different software have been made and used in simulation ofelectronic devices and circuits. One of the most popular and widely usedsoftware in designing and simulating electronic circuits is the LTSpice.LTSpice is a free-for-all computer software which utilizes SPICE (SimulationProgram with Integrated Circuit Emphasis) in designing and simulatingelectronic devices and circuits. It is a useful tool because it gives youguidelines on how your circuit design will work. It can also serve as a toolfor visualizing your desired circuit design before actually creating it.
And inLTSpice, the learning and testing a circuit will be more convenient because ofits feature that allows you to examine the waveforms on different parts of thecircuit. In line with this, the students have familiarized themselves with thebasic SPICE directives used in this laboratory experiment.Inthe first activity, a basic voltage divider was simulated. The .param command used designates thevalue of the resistor.
The .step param command used creates a step functionwhich varies from 1k to 10k with a step of 2.25k. The .
tran command calculatesthe non-linear algebraic-differential equations of the voltage divider circuitwith a stop time of 10 seconds. Then, in the second activity, we simulated alinear voltage regulator, namely the LT317A using the DC sweep function. The.dc command calculates the DC analysis of the voltage regulator circuit andincreasing or decreasing the applied voltage. In the third activity, wesimulated a second-order band-pass filter. The .ac command used calculates thesmall signal analysis of the filter linearized throughout its DC operatingpoint. And in the fourth activity, we simulated an ideal operational amplifierusing the transient analysis.
The transient analysis calculates the non-linearalgebraic-differential equations of the operational amplifier with a stop timeof 100 milliseconds. The .param command gives the resistors a fixed value.While in the fifth activity, we simulated a pulse signal using the pulsefunction from the voltage source. The signal created is similar to the signalused in the input/output ports of an Arduino microcontroller. The .tran commandcalculates the non-linear algebraic-differential equations of the voltagedivider circuit with a stop time of 40 milliseconds.
Lastly, in the sixthactivity, we simulated a full bridge rectifier using the step parameter. It hasan input voltage of 120 Vpk-pk and a frequency of 60 Hz to be converted to a120V pulsating DC. The step parameter displays the essence of using differentcapacitors as a filter, namely 10 uF, 90 uF, and 100 uF capacitors.