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it use in adjusting amount of current passing through a circle.
Stefanie Little
Wiki User
∙ 14y agoso that you can vary the amount of current flowing through a component - eg dimmer switch, volume knob, most of the controls on your TV
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If the rheostats are replaced by three incandescent lamps can you verify the thevenin's theorem?
gand mara
A device that decreases voltage?
Step down transformer, potentiometer or rheostats can all be used to reduce voltage.
What is working principle of rheostat in electric circuits?
The basic principle that rheostats use is Ohm's law, which states that current is inversely proportional to resistance for a given voltage. This means the current decreases as the resistance increases or it increases as the resistance decreases. Current enters the rheostat through one of its terminals, flows through the wire coil and contact, and exits through the other terminal. Rheostats do not have polarity and operate the same when the terminals are reversed. Three-terminal potentiometers can be used as rheostats by connecting the unused third terminal to the contact terminal.
Why rheostats have current ratings in additing to resistance rating?
So you don't try to put in more current than they can handle - so they don't catch fire.
Where a varying voltage is required this can be achieved by?
Variable resistors are called rheostats. A potentiometer can be used as a rheostat. Use the wiper terminal and one of the outside terminals for connections. The third terminal of the potentiometer is unused.
Why wouldn't copper work in a rheostat?
Copper would not be practical because of its high conductivity. The result of using copper would be that you would need to make very big rheostats to get any useful resistance.
What is a constant wire?
Constantan wire is a resistance-wire made of 42% nickel, 1.25% manganese, 0.25% iron and the rest is copper. It is mainly used in making wire-wound rheostats and potentiometers in electrical circuits.
How do you select field rheostat range for dc motor?
For a shunt dc motor the rheostat would vary from zero ohms to a value that produces the required minimum field current, but rheostats are not common with shunt motors except as a crude way of controlling the speed. Series dc motors normally use rheostats for starting, especially in trams etc. because the starting torque and current is very high. The rheostat resistance starts at a value equal to the supply voltage divided by the maximum allowable current drawn, and is reduced as the speed builds up.
What determines which one of the terminal of a rheostat in positive when connected in a series?
Electron flow is from negative(-) to positive(+), the rheostat would have to be on the negative side for the device being controled, before the device, e.g. light bulb.AnswerIt doesn't matter. Rheostats don't have positive or negative terminals.
Is a resistor a linear device?
Yes, if you are talking about the normal carbon composition types having colour codes. But there are some non-linear types too.
A formula prewritten by excel is called?
Function
What is the parent function for the exponential function?
The parent function of the exponential function is ax
