Practica 1 (Hecha 1) - Jair García

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Contents
Practice # 1	2
1.- The theoretical introduction	3
2. - Practice Development	4
2.1. - Using the ohmmeter.	4
2.2. - Using the voltmeter.	5
2.3. - Using the Ammeter	7
3. – Questionnaire	9
4. – Conclusion	10
5. – Practice Review	11
Practice # 1
"Use Ohmmeter, Voltmeter and Ammeter Measurements Cd"
The student will understand the proper handling of measuring instruments, so that at the end of practice, you should be able to: use good digital ohmmeter properly use the digital voltmeter. Use digital ammeter properly.
Material (Students)				 			Material (Laboratory)				
1 Breadboard.								1 Digital Multimeter.
Resistor 1K to 1 ¼ watt.							1 Source Variable Voltage.
Resistor 560Ω to 1 ¼ watt.
Resistor 680Ω to 1 ¼ watt.
Resistor 330Ω to 1 ¼ watt.
Wires for Connections.
4 Points Banana-Alligator.
2 Points Gator-Alligator.
1.- The theoretical introduction
The current or voltage can be measured by ammeters and voltmeters, Figure 1 shows two common forms of meters, one analog meter is a pointer that moves on a calibrated scale which depends on the angular deflection of the variable magnitude measuring. While the other is a digital meter which displays a series of digits in the display, indicating the magnitude of the measured variable. Figure 2 shows the symbols of the voltmeter and ammeter for use in electrical circuit diagrams.
Figure 1. a) Meter analog b) digital meter Figure 2. Symbol of each meter 
To measure the current in a circuit branch, that branch should be opened and the ammeter must be inserted so that it is connected in series with the element that is desired to know the flow. It is said that two elements are in "series" if one end of one merges with one end of the other, and there is a conductor connected to that union. The current flowing through this path, necessarily passes by the current meter (ammeter). To measure the voltage between two points, the voltmeter is connected in parallel with the electronic device that meet the desired voltage drop. Two two-terminal elements are connected in parallel if the terminals are connected one to the other terminals. Whether in such unions or not there is another connection. The essential characteristic of a parallel connection, through which elements the same voltage exists.
2. - Practice Development
2.1. - Using the ohmmeter.
Without energizing any circuit element, measure the resistance value presented by each resistor, as shown in Figure 3 and fill in the table 1.
	Resistance
	Measurement with Digital Ohmmeter
	Value With the Color Code
	R1
	0.99 Ω
	Café Red Black = 1 K Ω
	R2
	0.56 Ω
	Blue Green Coffee = 560 Ω
	R3
	0.699 Ω
	Blue Gray Coffee = 680 Ω
	R4
	328.8 K Ω
	Orange Orange Coffee = 330 Ω
Figure 3. Connecting Ohmmeter
 
2.2. - Using the voltmeter.
In figure 4 is shown how one measure the voltage should across the element. With the voltage source off, connect the circuit of Figure 5. Once armed the switch on the power circuit voltage and fill in the table 2.
Figure 4. Example of connecting the voltmeter.
 Figure 5. Circuit serial
	Voltage source
	Voltage R1 & R2
	Voltage R1
	Voltage R2
	Voltage R1 & R2
	Voltage R1
	Voltage R2
	E = 1 V
	1 v
	0.79 v
	0.202 v
	1 v
	0.751 v
	0.248 v
	E = 2 V
	2 v
	1.5 v
	0.5 v
	2 v
	1.503 v
	0.496 v
	E = 3 V
	3 v
	2.2 v
	0.7 v
	3 v
	2.255 v
	0.744 v
	E = 4 V
	4 v
	3 v
	1 v
	4 v
	3.007 v
	0.992 v
	E = 5 V
	5 v
	3.79 v
	1.25 v
	5 v
	3.759 v
	1.240 v
	E = 6 V
	6 v
	4.52 v
	1.49 v
	6 v
	4.511 v
	1.488 v
	E = 7 V
	7 v
	5.29 v
	1.74 v
	7 v
	5.263 v
	1.736 v
	E = 8 V
	8 v
	6.05 v
	2 v
	8 v
	6.015 v
	1.984 v
	E = 9 V
	9 v
	6.80 v
	2.25 v
	9 v
	6.766 v
	2.233 v
	E = 10 V
	10 v
	7.55 v
	2.4 v
	10 v
	7.518 v
	2.481 v
	E = 11 V
	11 v
	8.36 v
	2.7 v
	11 v
	8.270 v
	2.729 v
	E = 12 V
	12 v
	9.07 v
	3 v
	12 v
	9.022 v
	2.977 v
2.3. - Using the Ammeter
Figure 6 shows how to connect the ammeter to measure current in an element.
Figure 6. Ammeter Connection Example
Figure 6. Example of connecting the ammeter.
With the voltage source off, connect the circuit of Figure 7. Once armed the switch on the power circuit voltage and fill in Table 3.
	Current source
	Current R1 & R2
	Current R1
	Current R2
	E = 1 V
	3.32 mA
	9.70 mA
	1.44 mA
	E = 2 V
	6.30 mA
	3.10 mA
	2.98 mA
	E = 3 V
	9.60 mA
	5.30 mA
	4.42 mA
	E = 4 V
	12.90 mA
	6.94 mA
	5.93 mA
	E = 5 V
	16.23 mA
	9.00 mA
	7.41 mA
	E = 6 V
	19.49 mA
	10.52 mA
	8.88 mA
	E = 7 V
	22.64 mA
	12.21 mA
	10.43 mA
	E = 8 V
	25.76 mA
	14.25 mA
	11.88 mA
	E = 9 V
	29 mA
	15.95 mA
	13.41 mA
	E = 10 V
	32.25 mA
	17.80 mA
	14.83 mA
	E = 11 V
	35.80 mA
	19.47 mA
	16.35 mA
	E = 12 V
	38.9 mA
	21.33 mA
	17.78 mA
3. – Questionnaire
1. What is the characteristic of a series circuit?
A series circuit is in each end of an element is joined with the other. And there no one conductor connected with that union.
2. What is the characteristic of a parallel circuit?
The terminals are connected element with another, whether in such unions has another connection. The voltage is the same in each branch.
3. What is the main difference between a digital and an analog meter?
Analogue. It is calibrated manually, needles are used, and can have more room for error.
Digital. Automatically calibrates the margin of error is less when making measurements.
4. Why should not an ammeter connected in parallel?
Why not mark anything and if we put an ammeter in parallel, can become damaged, then, as your resistance is very small, the current will be higher in him.
The ammeter should be connected in series in the circuit. In order not to distort the measure should have a very small internal electrical resistance. Pay attention to the placement of these measuring devices.
The ammeters are connected in series with the circuit, i.e., interspersed between the points where one wishes to measure the current.
5. Why should de-energize the circuit when measuring the resistance of an electrical circuit?
Because to measure a resistance a current is passed through it, and if the resistance is already in an energized circuit, and a current went through it, so that the measurement would be the sum of the two currents, and therefore give an incorrect value.
4. – Conclusion
The practice is based on the identification of the main features that make a multimeter.
Use the ohmmeter to measure the resistance in different types of circuits, and the way to use the color coding of the resistances to show that this code displays the resistance value, which must be the same as the ohmmeter measure.
The practice is also focused on measuring the potential drop of circuits: series, parallel and mixed. The measurement was carried out with the multimeter voltmeter function, among other observations also denotes that the function multimeter voltmeter is used to measure voltage current into two types, for alternating current and direct current and the voltmeter has different types of ranges for measurements. Different arrangements of resistance is understood as follows.
The practice also requires circuits in series, parallel and mixed, will determine the various currents and you have a special care not to corrupt the source or multimeter since this practice is important to check the polarity.
The ammeter serve besides for measuring the current, which has a singularity shares with the voltmeter, since this also can measure two kinds of intensity and AC & DC.
5. – Practice Review
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