Digital Multimeter Technology - Essay Example

? Digital multimeter This article is about Digital Multimeter technology; its history and how it has evolved with time since it was invented up to the time that it was considered to convenient. The article goes ahead to provide graphical analysis of various equipments used in digital multimeter technology. Also presented are the symbols used to represent various devices like resistors, ammeter, voltmeter, capacitors and rheostat. Written analysis together with written statements is provided. The main objective of the of this article is to provide a user guide on Digital Multimeter technology as applied in the control of current flowing through a conductor. The user guide could be used by a number of individuals in order to achieve high performance and full control of various electrical installations. The research was undertaken in a school setting by involving students in active participation with the aid of user guides. The students were then assessed and the outcome recorded. The outcome was later used to upgrade the user guide. Table of Contents Table of Contents 2 Introduction 4 Background 4 Procedure 7 Resistors 12 Procedure for connecting resistors 12 Written Analysis 16 Written Statement 17 Concluding statements 18 References 20 Introduction Multimeter which is also known as multitester is an electronic gadget that integrates several measurement function of a unit. A multimeter has several features that have the ability to record current, voltage and resistance using the relevant electronic instruments. In the current world multimeter has been upgraded and may use digital and analogue technologies. In that case, they can be referred to as Analog Multimeter (AMM) and Digital Multimeter (DMM). Analogue technology measure signal in non-continuous form while digital measure signal in discreet form. Thus Analog instruments such as micro ammeter usually have a pointer which moves over a scale attuned for all the dissimilar measurements that can recorded while Digital instruments on the other hand display digits which are sometimes shown on a bar of a length relatively proportional to the magnitude being measured (Mazur, 2008). In real life situation, Multimeters can be used to correct faults that occur in electric circuit. This is because they posses high degree of accuracy. For example galvanometer is used to detect the presence of electric current and the direction of flow of electricity. This has helped over the years in various households and offices to prevent fire outbreak due to early detection of these faults. Background Men had a quest of acquiring a tool that he could use conveniently to measure and detect electric current thereby having full command of his environment regarding electricity. A lot of inventions were made by many inventors in order to quench this thirst; with the first ever moving pointer to be invented which had these abilities was the galvanometer. This was used across the board to measure resistance and voltage since it was the only device. It functioned with the aid of Wheatstone bridge. The device was known to be too slow when used in labs and in the fields. It was also bulky and delicate. Man then adopted the premise that there were more than were known to them, therefore he kept the fire blazing by conducting more research to acquire more practical and convenient devices. A meter which used fine metal spring was then discovered. Besides it detecting current it also had the capability of recording measurements by use of its magnetic properties. It was quick and easy to use. Multimeters were then invented in the early 1920s. They consisted of separate devices necessary for to maintaining telecommunication. As time went by, people became tired with carrying these separate instruments and this was a clear indication that a more convenient device was needed. Macadie invented a device which could record amperes, volts and ohms. It was later called Avometer since it was a multipurpose. His idea was later borrowed and used in developing Automatic Coil Winder and Electronic Equipment Company. By mid 1920s pocket watch meters were in use in many parts of the world (Davidson, 2010). This was so because they were cheaper than the Avometer. This watch had a metal feature which was connected to the negative connection an arrangement that resulted to more electric shocks, rendering the device more hostile. Vacuum Tubes Voltmeter were then invented and used for voltage measurements in electric circuits. They were later superseded by modern digital meters and some analogue meters, which have been used to date to achieve high input impedance. Nevertheless, scales like decibels, capacitance among others which produced sounds when the resistance measured is small have been used to acquire more fine results. Below is a digital multimeter GRAPHICS AND SYMOBLS Some of the symbols and instruments used as digital Multimeter are; Ammeter Used for measuring rate of flow of current passing at a given point of a conductor. Electric current is measured in amperes (A). The procedure for measuring current using ammeter is simply to Break the circuit open and Insert an ammeter in-line with the circuit so that all electrons flux through the path also passers via the meter. This makes the ammeter form part of the circuit and does not make much voltage drop. Its resistance is imperceptible and can also be placed in parallel. (Dellinger, 2011) Below is a circuit with ammeter in place. Voltmeter Is an instrument used to measure voltage drop across a conductor which is measured in volts. It can be connected in parallel. Its accuracy can be affected by temperature and other physical factors. Procedure Set the circuit Connect the voltmeter around each load such as cells, resistor and capacitors. Close the circuit and record the reading according to the scale. Below are both analogue and digital voltmeters DC current Direct current (DC) refers to flow of electric charges towards one specific direction. Electrons move from negative terminal to the positive terminal and this in turn induces current in an opposite direction; from positive terminal to the negative terminal. Photovoltaic cells and batteries are some of the objects that are known to produce direct current. Setting of DC current Consider the diagram below Identify a source of power Identify a load e.g. a bulb Connect the circuit using a wire or a cable and create a switch Close the switch to complete the circuit Figure 2 DC current How to measure DC current Review DC manual Read and understand the current and voltage limit for your DMM Set your meter to AMPS or DC Fit your clips to the correct hole Change to the right measurement style and continuum for the measurement to be recoded The figure below displays how to measure DC current NOTE: the only difference between measuring AC and DC is that the has to be changed from DC to AC. AC current The figure illustrates how to measure AC current using DMM In Alternating current (AC) the direction of flow of electric charges periodically changes Setting of AC current Set the source and the load in position as shown below The energy source is constantly changing First, electron movements are shown by continuous arrows With time, the source voltage begins to fall and reverses polarity The electrons will then flow in the direction of dotted arrows and in turn induce current in opposite direction. Figure 3 AC current The graph below summarizes AC and DC current Setting and Measuring of DC and AC voltage Change the multimeter to indicate DC or AC voltage Check that the two probes are fitted correctly Connect the probes to the terminals of at least 9.V battery Complete the circuit Measure the voltage drop across a resistor. Figures diagrammatic illustration of how to set and measure DC voltage Resistors A resistor is an electrical instrument used to gear electrical resistance in a circuit. They can be connected in series or in parallel. According to Ohms law, the current passing through a conductor is directly proportional to the voltage drop across it. Therefore the resistance is related to voltage and currents as I=V/R. the resistance of a conductor is measured in Ohms (Paul, 2001). Procedure for connecting resistors Break a set up circuit Insert a resistors in series Connect a voltmeter across each resistor and record the voltage drop Or connect the resistors in parallel Resistor measurement Switch the multimeter to indicate resistor Confirm that the probes are fitted correctly Conduct a confirmatory test using resistors that are not attached to the circuit Measure the resistance The diagram below shows how to measure resistance using multimeter A resistor can be represented using these symbols Figure 6 resistor connected in parallel Continuity test This is a test carried out to check flow of current on an electric circuit. It is done by putting small voltage across a chosen path. It can help to Detect if a wire is broken To make sure that something is not connected Whether the solder used is appropriate Continuity test procedure correct way of inserting test mode Switch off the power rectifier Join the two leads to voltmeter Put the voltmeter on not less than a two volt DC scale Connect the voltmeter leads to one of the objects being tested Record the voltage correct way of continuity testing Rheostat Also known as potentiometer and acts as a variable resistor thus voltage divider used for measuring electric potential Capacitors Capacitors are instruments used for leveling the flow of electric current in a conductor. Written Analysis The main purpose of setting this user guide is to help users in their manipulation of digital Multimeters in order to have a measurable control of these devices for a better stay. Other objectives include to help the beginners to be able to use the devices safely during their training and to educate the public on the dangers of mishandling electronic devices and other minor emerging issues about the Multimeters. Over the years, use of electronic gadgets has been on the rise due to high demand of electricity. Even though few casualties of electric shock have been reported, I feel it is very necessary that a guide on how to use the few devices present is paramount and thus much guidance should be made available to the public irrespective of whether the individual get an opportunity to handle these equipment or not. When guiding an individual on how to use a particular thing, a lot of keenness is essential. According to my explanation above, I have clearly put forward how to connect and safely use some of these equipments in order to control shocks and faults that are likely when dealing with large amount of current. Some of the equipment listed here are the most suitable devices when handling current in real life situations. When testing current using the ammeter the device is connected to the circuit and the reading is taken from the digits displayed on the screen for digital ammeters while the reading is taken from a scale for analogue ammeters. The current recorded can be used to draw assumption on how the current can be used and which kinds of loads suitable for that particular amount of current. This help to avoid wastage of current. Use of voltmeter is vital in detecting any device which can consume a lot of current thereby leading to insufficient power along the circuit. For instance when voltage drop across a conductor is minimal then the conductor is considered worthwhile and when the voltage drop is much the conductor is considered defective and it is withdrawn from the circuit. Voltmeters have also helped to identify materials which are referred to as good and poor conductors (Royston, 2003). Resistors are used widely in circuits to regulate the amount of current flowing to the lamps in most cases. Much current can lead to breaking of loads which they are suppose to drive; the loads may include HVAC systems, lamps among others (Kavanaugh, 2006). Due to these frequent breakages cost of living is always increased in the process of replacements. Written Statement In many cases guides are used widely to help the user to work smoothly and easily with any finished product. In this context, the user guide provided is to be used with reference to digital Multimeter technology in order to promote safe sail when dealing with all forms of electronic devices. In schools the user guide has been applied appropriately by students during practical’s which entailed connecting all the digital and analogue Multimeters. Many students were comfortable with the guide while could not relate the symbols used. Some had the problem of relating the resistors to voltmeters and ammeters while only a few had problems with understanding the digital Multmeters. In pursuit to address all these, I had to make the adjustments which included using more symbols where applicable. For example, for resistors and rheostat where the students complained that there was no distinction, I had to produce several symbols. When it came to relating the three variables I introduced Ohms law and provided the formula for detailed understanding y the students. Some of the outcomes from the students interaction with the user guide for digital Multimeter were; the guide provided better information for both the beginners and the students who had had accessed to the equipment and most of the students when later assessed could use the guide comfortably to connect both the digital and analogue Multimeters. The outcomes were as they are because the user guide was simple and clear. It was also sett elaborative and could speak for itself even in the absence of a human guide. In most cases electric line installations require much keenness that is acquired by practice and by use of relevant techniques in order to ensure safe and successful installation practices (Gibilisco, 2002). The user guide outlined here can be of help during the installation exercise. This is because most of the devices used to regulate flow of current to their required destinations include resistors, rheostat, and ammeter voltmeter among others. This qualifies the user to be of a broader application and in many areas Concluding statements Through research, it was noted that digital Multimeter could be used to improve students understanding of their technical subjects in schools. These disciplines include physics, chemistry and mathematics. This would in turn lead to production of competent engineers and responsible citizens of a nation. Many students get discouraged when they are not fully exposed to the equipments used and have gone ahead to term these subjects as technical. If only these user guides would be introduced in schools with proper guidance on how to use them, I do hope and believe that schools would be a better place for many students, not only those who love the subjects but to all other students. Besides, other means of regulating flow of electric current is a fact that we cannot deny. As things go hi-tech, new inventions come calling, we may use some means today which may not be appropriate in the near future and this has always made the engineering/ construction industry more challenging. With the emerging issues, disaster preparedness remains our outstanding challenge and more measures should be put in place in order to overcome these problems and to avoid them completely. That according to me is what remains to be leant. Some the shortcomings of the user guide are; the guide does not specify which type of clothing should be worn when carrying out these operations. Always when one carry out such operation, the environment is assessed and the type of the materials to be used, the type of protective clothing is decided. It does not also state the procedures that should be followed in times of accidents. It is quite clear that accidents cannot always be prevented from happening therefore the guide should also give first aid. The user guide can be used in several areas that include schools, telecommunication maintenance, motor vehicle lighting systems, street lighting, house lighting among others. In named places use of large amount are always involved. Generally, digital multimeter has of late been very instrumental in controlling amount of current flowing through a conductor. This has helped in safe installation and easy maintain of various electric gadgets (Linsley, 2011). References Davidson, H. L. (2010). Pocket digital multimeter techniques. Blue Ridge Summit, PA: Tab Books. Dellinger, J. H. (2011). High-frequency ammeters. Washington: Govt. Print. Off.. Gibilisco, S. (2002). Teach yourself electricity and electronics (3rd ed.). New York: McGraw-Hill. Kavanaugh, S. P. (2006). HVAC simplified. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers. Linsley, T. (2011). Advanced electrical installation work (6th ed.). Amsterdam: Elsevier/Newnes. Mazur, G. (2008). Digital multimeter principles. Homewood, Ill.: American Technical Publishers. Royston, A. (2003). Conductors and insulators. Chicago, Ill.: Heinemann Library. Paul, C. R. (2001). Fundamentals of electric circuit analysis. New York: John Wiley & Sons. Glossary Digital- system that uses data in discrete form Analogue- system that measures data in continuous form Ohms- units for measuring resistance HVAC- heating, ventilation, and air conditioning Decibels- scale measuring audible sounds. It is subject to human hearing. Capacitance- ability of a capacitor to store charges it symbol is C Appendices Step down transformer converts the magnetic field around the conductor into a small AC current that is audible to the ammeter. When the resistors are connected in series the total resistance is equal to the sum of all the resistors, while when the connection is in parallel the total resistance is equal to the sum of the reciprocal of the individual resistors. Read More