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Q1. When the null point is acheived, then the current is the current through KLMN and ABRS same? If yes, then why? if not then why not? Q2: PLease tell me why the Current through the resistances will be same in both the cases?




Q1. When the null point is acheived, then the current is the current through KLMN and ABRS same?


 If yes, then why? if not then why not?


 


Q2:



PLease tell me why the Current through the resistances will be same in both the cases?



Grade:

1 Answers

SAGAR SINGH - IIT DELHI
878 Points
13 years ago

Dear student,

There are many instances where only a portion of an output voltage from a signal source is needed. If we allowed the full output voltage from a home CD player to be driven into the input of an amplifier, the amplifier would play at or near full power at all times. This would become quite annoying in a very short period of time. To reduce the overall volume, we need to allow only a fraction of the full signal through to the amplifier. To control the level of the signal, we use a potentiometer. A potentiometer (also know as a 'pot') is a modified resistor. Potentiometers can be used to allow a change in the resistance in a circuit or as a variable voltage divider (in the case of a volume control). If you have a rotary volume control on your TV or radio, it is (more than likely) a potentiometer being used as a variable voltage divider.* A potentiometer generally has 3 terminals. 2 of the terminals are connected to the opposite ends of a resistive element. The 3rd terminal (usually, is physically in-between the other 2 terminals) is called the wiper. The wiper is a contact (actually, generally many very small contacts) that slides along the resistive element. The diagram below shows the schematic symbol for a pot.

 


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