Calculating unknown resistances by wheatstone bidge, Physics

Calculating unknown resistances

The current through the galvanometer (G) - a very sensitive ammeter, is reduced to zero by adjusting R4.  The bridge is then said to be balanced.  When the bridge is balanced, the voltage at A is equal to the voltage at B and no current flows between A and B.

424_wheat stone bridge.png

 

Hence       VR1             =       VR2

          therefore   I1 ´ R1           =       I2 ´ R2 ------------- (1)  (by Ohm's law)

          Also           VR3             =       VR4

          therefore   I1 ´ R3        =       I2 ´ R4 ------------- (2)

 

 

Dividing (1) by (2) 1368_Calculating unknown resistances.png

 

Therefore the unknown resistor  R3  = 1887_Calculating unknown resistances1.png    (all known values)

In calculations it is possible for any of the four resistors to be unknown.  However, provided that the bridge is balanced, the theory remains the same and all that is required is to transpose the equation to find the unknown 

 

Posted Date: 9/13/2012 3:51:58 AM | Location : United States







Related Discussions:- Calculating unknown resistances by wheatstone bidge, Assignment Help, Ask Question on Calculating unknown resistances by wheatstone bidge, Get Answer, Expert's Help, Calculating unknown resistances by wheatstone bidge Discussions

Write discussion on Calculating unknown resistances by wheatstone bidge
Your posts are moderated
Related Questions
what is resistor filter?

What is Joule Cycle? Find the efficiency of the Joule cycle, consisting of two isobars and two adiabats.  Presume that the heat capacities of the gas C p and C v are constan

Explain Resistance Resistance:   Interaction among flowing charges and atoms in electric circuit which resists (slows) current flow SI units:  volt per ampere ≡ ohm (Ω)

Violet light (λ = 415 nm) falls on a slit that is 0.040 mm wide. The distance among the centers of the central bright band and the third-order dark band is 18.7 cm. What is

The potential difference across a 4 ohm resistor is 20 volts.  Assuming that all of the energy dissipated by this resistor is in the form of heat, how many joules of heat are radia

SHAPE MEMORY ALLOYS: A group of metallic materials that can return to some previously defined shape or size when subjected to the appropriate thermal producer. That is to say, s


If the thickness of the slab is increased what happens to lateral shift?

a column of water contains fine metal particles of radius 2*E(-8) m, which are in thermal equillibrium at 298 K. if there are 1000 particles per unit volume at a given height,how m

The speed at which a wave propagates down a string is 300 meters per second.  If the frequency of this wave is 150 Hertz, what is the wavelength of this wave? Ans: The wavel