Electrical Measurements Lab Report From The Digital NI Elvis Board

Introduction:

This Electrical Measurements Lab is designed to give students an introduction to talking measurements from a breadboard. Students have two available methods for taking voltage, current, and resistor measurements. One of which, is to use a standard multimeter to take measurements. However, all measurements in this lab report come from the digital NI ElVIS board.

A. Resistance:

Given three resistors of different color codes, the theoretical resistance can be found by apply the standard color code. Following this value, one can find the actual resistance by using the multimeter feature of NI ELVIS by attaching the positive and negative leads of the board to the resistor ends. Once we have a theoretical and actual resistance we
After applying this method, one can find Rskin. This value is massive compared to the resistors we are using in this lab. Therefore most of the current will go through the resistor while very little amperage will move through one’s body. This makes it seem safe to hold the leads of the resistors. However, given a large enough resistance to be measured and enough current a human body can be harmed. We can now use the formula for Rt to calculate the resistance of a parallel circuit between ones body, infinite resistance, and R1. (Rt)

B. Voltage:

The main goal of exercise B is to teach students to safely and accurately take voltage measurements. Using the same circuit that was built to determine Rtot, we can take measurements of the voltage on multiple elements. We can see that the voltage source is close to 15V but not exactly the correct value because it is not a perfect source.

From figure B-1 we can obtain V1 and Veq. Due to the method of measuring described by the positive and negative symbols, both V1 and Veq will be positive. Checking this data, we can use Kickoff’s Voltage Laws(KVL). This law can be thought of, as all elements giving voltage and absorbing voltage must sum to zero. Equation B-1 shows that this is very close to a true equation but due to imperfect measurements and slight changes to the circuit to get measurement, the
This is due to the passive sign convention and how we measure voltage. The current determines the sign of voltage. The passive sign convention states that current must be going into the positive lead of the multimeter. Although by absolute value these two schematics are correct, the first schematic, pictured in figure B-1, is the correct way to take voltage measurements. The first method fills all of the laws of the passive sign convention. If we were to use KVL without changing the sign of Vs then we have a very incorrect equation. However, since we know that resistors absorb power, we can assume the sign of Vs to be negative as