it is used for prevention of over flow of current and for maintaining irrespective regulation
AnswerA resistance box is a piece of laboratory equipment consisting of an electrically-insulated box, containing a number of resistors which can be connected, externally, via a pair of terminals. The resistance can be adjusted in fixed amounts by inserting or removing metal pegs into a slotted bar; this arrangement either adds or removes the fixed resistors into the circuit.
a box which has resistance between 1 ohm to 50000 ohm
The use of a resistance box or a "Decade Box" is to help calibrate instruments used to measure electrical values such as Voltage, Current, and Resistance. Without them you would not have a known value of resistance to use as a set point.
Resistance decade box is nothing but Resistance bank. It has various ranges of Resistance value ranging from few ohms to few mega ohms. In other terms, large value of resistance are fabricated in single box is said to be Resistance decade box.
we use it when we require a variable resistance in a circuit
It depends on what you want to accomplish. If you want to decrease the resistance in a circuit, you would place the box in parallel to some other resistor. If you want to increase the resistance in a circuit, you would place the box in series.
To calculate the resistance for a slip ring motor, there is an equation that must be solved. This is Torque = S/R. S is the slip of the motor and R is the resistance of the motor.
The wires in the resistance box are double folded to reduce their resistance value by a factor of 4, as resistance is inversely proportional to the cross-sectional area of the wire. This allows for more precise resistance increments to be achieved by varying the length of wire exposed in the circuit.
Resistance box will provide resistance of discrete values such as 1, 2, 3 ohms or 0.1,0.2, 0.3 ohms. So interim values are not possible. But rheostat gives a chance to vary the resistance continuously. It may be 5 ohm or even 5.769 ohm. So just to fix current for a specified value such 1.5 ampere resistance box will not be suitable where as a rheostat is the most suitable.
A resistance box is a device that contains a set of fixed resistors that can be connected in various combinations to achieve different resistance values. A rheostat is a variable resistor that can be adjusted to change the resistance in a circuit. A resistor is a general term for a component that resists the flow of electrical current in a circuit and comes in fixed resistance values.
it is used for prevention of over flow of current and for maintaining irrespective regulationAnswerA resistance box is a piece of laboratory equipment consisting of an electrically-insulated box, containing a number of resistors which can be connected, externally, via a pair of terminals. The resistance can be adjusted in fixed amounts by inserting or removing metal pegs into a slotted bar; this arrangement either adds or removes the fixed resistors into the circuit.
At terminal velocity, the air resistance acting on the falling 100-N box of nails would be equal in magnitude to the weight of the box, or 100 N. This means that the net force acting on the box would be zero, resulting in a constant velocity.
Slide wire rheostat: We can get continuous variation in resistance. It is used in such situations where we are supposed to get a fixed current flowing throug the circuit-some integral value like 1,2 etc instead of 1.343 and all. Resistance box: It is a deveice used to get a specific value of resistance. We may not get a simple value for current.