This report presents a more realistic model of a resistive potentiometer and shows how qucs can be used to develop practical models of this fundamental component that give an order of magnitude improvement over the commonly used two resistor models. The potentiometer is an electric instrument that used to measure the emf electro motive force of a given cell, the internal resistance of a cell. Thermo scientific 616210r this product has been made available for purchase due to recent demand, however information about the product is limited. Keep it simple dont use too many different parameters. Theory the purpose of this experiment is to measure the electromotive force emf and internal resistance of a dry cell. Learning electronic theory is all well and good, but like most real tasks, electronics is 20% theory and 80% practice. Lab 10 physics 2l laboratory report potentiometer laboratory no 10 written by mohamed amine radoui lab partner ahmad abuamara kyle olson prya. Jan 12, 2020 a potentiometer is a passive electronic component. Connect the positive terminal of the ammeter to the positive terminal of the test cell. The most common form of the potentiometer is the single turn rotary potentiometer.
Balance the potentiometer by moving the slider to the left, not by changing the 3dial. A potentiometer is a cheap electric controller used for everything from dimmer lights to electric guitars. Thermo scientific potentiometer potentiometer fisher scientific. P otentiometers are transducers that translate a rotary or linear displacement into a change in resistance. Slide wire potentiometer, battery or power supply, rheostat, double poledouble throw dpdt switch. A circuit diagram is presented for a potentiometer used to verify the nernst equation and investigate other electrochemical phenomenon.
As always, prelab questions are to be done individually, and the lab is to be done with your lab partner. Potentiometer for the general chemistry laboratory journal. The ends of the resistance element are attached to two input voltage conductors of the circuit, and the third contact, attached to the output of the circuit, is usually a movable terminal that slides across the resistance element. Compare your circuit to the detailed diagram in section iv. Some of the applications are listed below, categorically. Diagram of control panel 1 temperature setting potentiometer 2 telethermometer 3 onoff switch with green indicator lamp 4 orange indicator lamp 5 safety thermostat indicator lamp 5. Thumbwheels and shafts can be provided either separately or already inserted in the potentiometer.
As you turn the potentiometer your adc readings should vary. Potentiometer testing determining which potentiometer is best for longterm use in severe environments. This laboratory manual is intended for use in a dc electrical circuits course and is appropriate for two and four year electrical engineering technology curriculums. You can see the first balancing length in the popup. You can see the second balancing length in the popup. Since this varies from potentiometer to potentiometer we will set up a voltage divider, as shown below, and take the ratio. Laboratory manual for dc electrical circuits dissidents. These metrics are regularly updated to reflect usage leading up to the last few days.
A wheatstone bridge is a circuit used to measure the resistance of an unknown resistor. Apr 14, 2016 for the love of physics walter lewin may 16, 2011 duration. Like the wheatstone bridge, the potentiometer exists in both slidewire and box forms. Welcome to the online version of the the potentiometer handbook originally published. See section 6 for more detail about specific analytes. The potentiometer is also called as pots and it one of the most commonly used devise for measuring the displacement of the body. The emf of a cell may be defined as the terminal voltage of the cell when not under load, that is. The resistive element is designed to follow a logarithmic taper, aka a mathematical exponent or squared profile. As you turn the potentiometer, it increases the resistance, lowering the lights or the volume on the guitar.
Digital potentiometers design guide microchip technology. Different materials are used to construct potentiometers, including carbon composition, cermet, conductive plastic, and the metal film. In this experiment, the potentiometer consists of a long uniform wire with a constant current in it and a method for inserting, sequentially, a standard cell for calibration and the unknown cell for measurement. The resistance between the wiper b and either side of the outer terminals a or c. The circuit of a simple dc cromptons potentiometer theory is shown in the below figure. If a sensitive indicating instrument is used, very little current is drawn from the source of the unknown voltage. Potentiometer for the general chemistry laboratory. Basically this means the center position of the potentiometer is not one half of the total value of the potentiometer. Acps potentiometers can be adjusted from either side, both in the. Potentiometer working principle animation instrumentation tools. Youll communicate with a digital potentiometer chip from a microcontroller. Potentiometers are widely used to control the output of electrical devices e. Laboratory manual for physical chemistry where t0 is the freezing point of the solvent.
Fiore is ed under the terms of a creative commons license. Laboratory potentiometer all industrial manufacturers. In this experiment, you will use a ph meter to follow the course of acidbase titrations. Connect the other terminal of the resistor to the 0. It has a resistance element that is attached to the circuit by three contacts, or terminals. In this lab, youll see synchronous serial communication in action using the serial peripheral interface spi protocol. Laboratory 2 parts list more resistor networks and. Between the two ends the resistance is nominally 10k. Clinical chemistry is the branch of laboratory medicine that focuses primarily on molecules. The potentiometer is the electrical type of transducer or sensor and it is of resistive type because it works on the principle of change of resistance of the wire with its length. Slide the jockey along the potentiometer wire to obtain the null point.
Introduction this is a relatively short laboratory, because you will also be assembling your microblip, a customized device based on the arduino micro, which functions as a blip breadboard laboratory interface processor, simulating a number of useful electronics. A potentiometer is a type of variable adjustable resistor. A potentiometer has the two terminals of the input source fixed to the end of the resistor. Some browser pdf plugins cannot handle urls spanning multiple lines. The tests in a clinical chemistry laboratory measure concentrations of biologically important ions salts and minerals, small organic molecules and large macromolecules primarily proteins. This laboratory manual for dc electrical circuit analysis, by james m. Dc cromptons potentiometer or laboratory type potentiometer.
A potentiometer essentially works as a voltage divider, however it is used in many industries and applications too. To compare the emf of two given primary cells daniel and leclanche cells using a. A scaling factor is determined based on the use of a calibration jig and gauge blocks meeting the requirements of astm d6027 and e2309. For the love of physics walter lewin may 16, 2011 duration. A logarithmic taper potentiometer is a potentiometer that has a bias built into the resistive element. This is different to a rheostat, where here one end is fixed and the sliding terminal is connected to the circuit. Use the resistor color code in the introductory section of this manual to identify the. And also it is used to compare emfs of different cells. To adjust the output voltage the sliding contact gets moved along the resistor on the output side. A potentiometer is a variable resistor consists usually of a turning dial to change the value of its resistance between two of its terminals.
Connect different electrical components as shown in. Potentiometer operation as described in the lab lecture the potentiometer is a three terminal device. Just because a circuit works in a simulation does not mean it will work in real life. A wide variety of potentiometer laboratory options are available to you, there are 122 suppliers who sells potentiometer laboratory on, mainly located in asia. Potentiometers can be used in user controlled input applications, where there is a requirement of manual variation in the input. Select the range selection switch at the point where the meter reads least possible value of voltage. Microchip offers digital potentiometer devices with typical endtoend resistances of 2. There is one dial switch with fifteen steps, each having a precision resistor. Separate search groups with parentheses and booleans. Laboratory 2 more resistor networks and potentiometers. The manual contains sufficient exercises for a typical 15 week course using a two to three hour practicum period. The heart of the potentiometer is a resistive strip inside it through which one can adjust the amount of resistancevoltage to pass in a circuit through it.
The resistance between the wiper b and either side of the outer terminals a or c varies from zero to a maximum of the full rating of the pot. Find your laboratory potentiometer easily amongst the 7 products from the leading brands on directindustry, the industry specialist for your professional purchases. The terminal voltage of a cell is the potential difference between its terminals. Thermo scientific potentiometer potentiometer fisher.
Physics 2l laboratory report potentiometer laboratory no. Potentiometer working, their applications and different types. Now drag the plug and insert it in the second gap of the two way key. The top countries of suppliers are china, india, from which the percentage of potentiometer laboratory supply is 98%, 1% respectively.
This type of potentiometer is often used in audio volume control logarithmic taper as well as many other applications. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals. Slide wire potentiometer, battery or power supply, rheostat, double poledouble. From the resulting titration curves, you will determine the concentrations of the acidic solutions as well as the acidionization constant of a weak acid. A potentiometer made from homogenous resistance wire of length l and resistance r l al is used to changed voltage at an appliance of resistance r find the voltage across and current through a resistor r as a function of the distance x of the sliding contact from the end of the potentiometer. In order to calibrate a voltmeter and to contrast the emf of a cell with its terminal voltage. Potentiometer for the general chemistry laboratory journal of chemical education.
In a potentiometer, the entire input voltage is applied across the whole length of the resistor, and the output voltage is the voltage drop between the fixed and sliding contact as shown below. Citations are the number of other articles citing this article, calculated by crossref and updated daily. This explains laboratory type or cromptons dc potentiometer theory,brooks deflectional,standard cell dial,vernier,precision type,multiplerange potentiometers. To measure the emf of an unknown cell using a potentiometer. View lab report lab 12 from phys 2 at south dakota state university. It can also use as a variable resistor in most of the applications. Potentiometer working principle animation potentiometer also known as pot is generally used in circuits to provide variable resistance or variable voltage. Spi communication with a digital potentiometer itp. Potentiometer, 012 volt power supply, flashlight, standard cell, galvanometer, double pole switch, slide wire resistor, carbon pile resistor, voltmeter and resistor decade box. Calibration potentiometer article about calibration. Abstract the main purpose of this experiment is to use the potentiometer to measure the emf of a cell.
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