Experiment I
Simple Voltage and Current Measurement
Objective
The objective of this experiment was to measure the Voltage and Current. Upon completion of this experiment I was able to:
1) Set the DC power supply to a specific voltage.
2) Properly connect the voltmeter to measure voltage.
3) Measure current with the ammeter.
4) Measure resistance with the ohmmeter.
5) Determine the accuracy of a given meter reading.
Theory
The theory required for this experiment was an understanding of Ohm’s Law. Ohm’s Law is the algebraic relationship between voltage and current for a resistor. Resistance is the capacity of materials to impede the flow of current or electric charge. Ohm’s Law expresses the voltage as a function of the current. It was also necessary that the concept of measurement accuracy be understood. This is discussed below.
Accuracy is of primary importance in an experimental work. The tolerance quoted by the meter manufacturer allows us to calculate the accuracy of any reading taken with that particular meter. For example, assume that the dc voltage scale on a particular multimeter is rated at ± 3% of full scale. This means that a reading on the 10V scale is accurate to (± 0.03%)(10) = ± 0.3V. Thus, a reading of 9V on the10V scale indicates a true voltage, which lies between 8.7 and 9.3 V. A reading of 1V on the scale would indicate a true voltage between 0.7 and 1.3 V. At this point, the error is ± 30%! Any reading less than 10% of full scale should be viewed with suspicion since most meters are very inaccurate n this range.
Circuit Diagrams
For this experiment we used a Power supply source, voltmeter/ammeter/ohmmeter.
Fig 1.1 Power Supply and voltmeter in parallel
Power Supply Voltmeter
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Fig 1.2 Simple voltage measurement circuit.
a a
b a b a a d c c d
c d
Fig 1.3 Simple current measurement circuit
Power Supply
(Be sure current I control is at maximum setting)
Fig 1.4 Circuit to measure resistance
Procedure
To measure the voltage output of the power supply, we connected the voltmeter as shown in Fig. 1.1. We made sure that the voltmeter is always connected in parallel with the voltage being measured. Before turning on the power, we set the voltmeter voltage range to a DC value higher than the highest voltage we expected to measure. This precaution must be observed with all meters in order to avoid the possibility of burning out an expensive instrument.
We then set the current control to maximum current and adjust the output voltage of the supply to values of 2.5, 10, and 15.
the mass and initial temperature of the water. Next, impale the food sample on the needle. Next, light
In figure 2, the class mean calculated was 147.8kJ. The difference between the two measurements is 2,122.2kJ. This shows how low the accuracy for this experiment was. The macadamia nuts had a true energy value of 3040kJ per 100g. Looking back at figure 2, the class mean calculated was 224.4kJ which leaves a difference of 2,815.6kJ. Once again, a low accuracy. Lastly, the popcorn had a true energy value of 1910kJ. The class mean equalled to 144.1kJ. The difference between the class mean and the true value is 1,765.9kJ which shows this experiment being low in
Then we used the calculated slope and the accepted value of 980 cm/s2 to calculate the experimental error:
readings at 20, 30, 40, 50 and 60°C from which a trend should show. I
Placed 30 mL of water within a beaker and placed the metal sample within the beaker. After placing the metal sample within with beaker the volume of water in the beaker changed. The volume change was recorded for the volume of the metal sample.
After calculating all the values, we put it in a graph to compare the density, mass, and volume by using
voltage. But this method can be hard as you might not be able to know
This is due to the small changes in mass. The values are only significant with more decimal places, but cannot be shown on the electronic balance. As a result, the machine rounds off the values when they overreach the range of the
It was probably either not functioning right or had not been adjusted correctly. If another balance scale was used for the procedure maybe the data could have been more accurate. To continue, another mistake that could have lead to poor data was when pouring the unknown metals into the graduated cylinder to measure the volume, some metals had fell to the ground and only the seen metals was picked up. Some of the metals could have been left on floor after measuring. This loss of metal may have resulted in losing a few grams of the unknown metal. This could have been avoided if the procedures were taken more carefully and slowly whereas no mistakes could've happened. Just like in any experiment, there are errors just like there was in this experiment. The lesson is to learn and improve from the errors on the previous experiments. To improve from the errors, is to use a modern balance scale to recieve a more accurate results. Most objects disfunction as time goes by. Also, the measurements could have been more precise. A more precise measurement could lead to a more accurate calculation. When having a time frame for a procedure, knowing how to manage your time and not rushing through the steps could help the experiment be a success. In every experiment there will be errors that will carry on and remember to not repeat the mistakes
measurements at the highest frequency that will provide a measurable voltage. Report data in a graph. Calculate the bandwidth of the voltages that were measured.
After they either went all the way to the highest voltage or they gave up, they were told that the
Before learning the methods from the computer tutorial, I was confused about certain test. B...
3. Place a sheet of filter paper on to the scales and then set scales
This summer when you go to weigh that fat juicy watermelon, think about the mechanics of how the scale works. The basket is attached to a spring that stretches in response to the weight of the melon or other objects placed in it. The weight of the melon creates a downward force. This causes the spring to stretch and increase its upward force, which equalizes the difference between the two forces. As the spring is stretched, a dial calibrated to the spring registers a weight. When designing scales one needs to take into account that every spring has a different spring constant (k). Bloomfield (1997) defines k as “a measure of the spring’s stiffness. The larger the spring constant-that is, the stiffer the spring-the larger the restoring forces the spring exerts” (p. 82).
Then the ITS test is performed on the sample at 77°F (25°C) at a loading rate of 2in/min.