1. In the wheatstone bridge circuit, R1 & R4 have a resistance of 300 ohms each. R2 & R3 each have?

Question

if 150 ohms. The source voltage is 100 volts. What is the current thru to galvanometer if its resistance is 50 ohms.

here's the pic: http://i20.photobucket.com/albums/b243/bhabyabie/problem1.jpg

R1(upper left)

R2(upper right)

R3(lower left)

R4(lower right)

2. Use te delta-wye transformation to determine what voltage must be applied to the input terminals of the lattice network of the figure below in order to draw a 2 ampere current from the source when a 20 ohm load is connected to the output terminals of the network.

here's the pic: http://i20.photobucket.com/albums/b243/bhabyabie/problem2.jpg

Answer 1

1. Left side of bridge forms a voltage divider 300 an 150.  150/450 = 0.3333

Voltage at left of galvanometer = 33.333 volts

Right side of bridge forms a voltage divider 150 and 300.  300/450 = 0.6666

Voltage at left of galvanometer = 66.6666 volts

Voltage across galvanometer = 66.6666 - 33.3333 = 33.3333 volts  

33.3333 volts / 50 Ohms = 0.66666 Amps.

(I cannot see the photo, so you'll have to get the sign of the current correct).

2. Photobucket photos are blocked on my server, so I can't see the circuit.  sorry....

Your word description of problem 1 was sufficient for solving it.

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