Measuring Resistance & Voltage using Multi MeterLab#02

LAB#02

OBJECTIVE

To determine the value of resistance and voltage using Multi Meter.

EQUIPMENT REQUIRED

  • Multi Meter
  • DC Power Supply
  • Different Valued Resistors

THEORY

MULTI METER

This instrument is widely used in laboratories and for general purpose testing because of its ability to measure either voltage, current or resistance, depending in the setting of the selector switch. The other name of Multi Meter is Volt Ohm Ammeter (VOMs) and Digital Multi Meters (DMMs)

VOLTMETER

A voltmeter is an instrument designed to measure voltage, it can be connected across the terminals of a voltage source to measure the voltage produced by the source. The + and – symbols on the voltmeter shows the connection of the polarity. Red terminal to + and Black terminal to -.

OHM METER

An ohm meter is an instrument designed to measure the resistance. Resistance is never measured when there is a voltage source connected across it or when there is any other component connected to it.

PROCEDURE

PART 1: Tomeasure the value of the Resistance using Ohm Meter

  • To measure the value of the resistance simply connect the probes of the ohm meter to the resistor whose resistance is to be measured.
  • Resistance is never measured when there is a voltage source connected across it or when there is any other component connected to it.
  • Select the appropriate range using selector switch on ohm meter so that the resistance of the resistor falls into that range other wise no reading would be appeared on the ohm meter.
  • There is no positive or negative terminal marked on the resistor so it is your choice to put either red or black probe to either end of the resistor.

PART 2: To measure the value of the Voltage using Volt Meter

  • To measure the value of the voltage simply connects the probes of the volt meter to the probes of the DC Power Supply.
  • Selector switch should be on Volt DC.
  • Select the appropriate range using selector switch on volt meter so that the voltage falls into that range other wise no reading would be appeared on the volt meter.
  • While measuring the voltage, connect the positive terminal of the voltmeter to the positive terminal of the DC Power Supply and vice versa otherwise minus sign appeared on the voltmeter.

OBSERVATIONS

TABLE 2.1

Measured Resistance Versus Color Coding Resistance Values

Resistors / Measured Value
(VOM/DMM) / Calculated Value
(Using color code) / Falls Within specified
tolerance (Yes/No)
Sample / 23Ω / 22Ω / Yes

TABLE 2.2

Applied Voltage Versus Measured Voltage

Applied DC Voltage in Volts / Measured DC Voltage in Volts
5 volts
10 volts
15 volts
20 volts
25 volts

EXERCISE

Q1) Shown here is the schematic symbol for a resistor:

What is the purpose of a resistor? What function does it perform? Also, draw an illustration of whata real resistor looks like______

Q2) Many resistors have their electrical resistance shown by a set of color codes, or”bands,” imprintedaround their circumference. A standard color code associates each color with a specific decimal digit (0through 9). Associate each of the following digits with its respective color:

0 =

1 =

2 =

3 =

4 =

5 =

6 =

7 =

8 =

9 =

Q3) What does the last color band represent on a color-coded resistor? ______

Q4)Determine whether or not the following resistors measure within the resistance range specified by their color codes:

  • (Yellow, Violet, Orange, Gold) Measured resistance = 44.68 k Ω ______
  • (Grey,Red,Brown,Silver) Measured resistance = 905Ω ______

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