There were several goals of this project. The main purpose of this project was to become familiar with new software tools such as TinkerCAD, LTSpice, and Deepnote. Learning how to generate circuit simulations in TinkerCAD and LtSpice, then taking the data that was recorded and import it into Deepnote to generate a plot of the data that was collected from each program. This project had the objective of learning the purpose of a voltage divider, how it works, and the way it correlates to ohm’s law to find the value of an unknown resistance based on the voltage input and output
Voltage Divider & Ohm's Law
A voltage divider is a type of circuit that uses multiple resistors to alter the output voltage of a circuit. This type of circuit uses a ratio between two resistors to lower the voltage to protect from sending too much voltage to an object within the circuit that operates at a lower voltage than the voltage that is supplied from the power source. The equation for a voltage divider is; Voltage Out = Voltage In * (Resistance 2/(Resistance 1 + Resistance 2)) .
Ohm’s Law is a law that stating that the current between two points is directly proportional to the voltage across two points within a conductor.The law uses current “I” and resistance “R” to find the voltage ‘V” of a circuit. The equation being V = IR. When working to find an unknown resistance of a resistor in a circuit like was done in this lab, ohm’s law can be used by subtracting the voltage input by the voltage output and dividing that difference by the resistance value of the known resistor. The equation is this; Resistance of R2 = (Voltage Output - Voltage Output)/(Resistance of R1).
Circuit Setups & Data Collection:
In both TinkerCAD and LTSpice similar circuits were built. This project consisted of a simple circuit that contained a power supply that varied from 0 to 10 volts. The power supply was connected to a resistor and a photoresistor that are in series to create a voltage divider. Both circuits were created based on the tutorial videos by Dr.Spicklemire found in the original instructions of this project. The data recorded in both software consisted of the input voltage and the voltage across the photoresistor in increments of 1 volt from 0 -10 volts.
TinkerCAD: In the TinkerCAD circuit there was a known 1000 ohm resistor and an unknown photoresistor. The data in this simulation was recorded manually in an excel sheet then uploaded to Deepnote as a .csv file.
Lt Spice: In LT Spice there is no option to use a photoresistor so the circuit had 2 know resistors with a resistance of 1000 ohms each. This software records the data automatically when you run the simulation, so it recorded the voltage of the input and the voltage between the 2 resistors. The data was uploaded to Deepnote as a .txt file but was read as a .csv file.
Code and Graph
Results: The graph of each simulation compares the voltage across the photoresistor to the current through the photoresistor to generate the resistance of the photoresistor, represented by the blue plot points. The red line through the graph displays the theoretical resistance as a reference to compare to the actual resistances recorded at each interval. The slope is the resistance of the voltage divider. The slope of the TinkerCAD data is 670.2 ohms and the slope of the LTSpice data was 1000 ohms. TinkerCAD Code&Graph LTSpice Code&Graph