Potentiometer has gained many aspects in the field of science and especially in the field of physics as it is a three-terminal resistor with a sliding or rotating contacts that forms an adjustable voltage divider and another aspect is that it is a measuring instrument which is essentially a voltage divider used for measuring electric potential. These are normally used to control electric devices such as volume control in audio equipment. Most importantly they are designed to control directly the significant power since it is dissipated in the potentiometer and it would be comparable to the power in the controlled load. There are so many names used in electronics to describe the specification of that particular device so is the case with a potentiometer as nomenclature plays very important role in the working and identifying the device.
What are its applications?
Mainly potentiometer are used to control a specific power of a watt or so or it is directly controlled instead of this they are used to adjust the control of analog signals such as volume control of audio equipment. Another example could be a light dimmer that uses a potentiometer to control the switching of the TRIAC or to control the brightness of the lamp indirectly. But since then the concept of use of potentiometer has been widen spread as in present potentiometers are widely used throughout electronics wherever there are adjustments to be made during manufacturing or services.These are widely used as user control, and could control very wide variety of equipment factors. Though its uses are declined in 90s with rotary incremental encoder stillthey make their way in the volume control and as position sensors.
Comparing EMF of two cells and measure g it by different methods.
There are two methods by which EMF of a cell can be compared with the EMF of two cells one is an individual method and the second is the difference method. In individual method when two cells are connected in series such that the negative terminal of one cell is connected to the positive terminal of the other cell and then only those cell are said to assist each other which can calculate the sum of both cell. In difference method when a positive terminal of a cell is connected to the end of potentiometer wire then the negative terminal is connect to galvanometer and this lead the current to flow at constant speed and at constant charge of the current.