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>> Electric Current
>> Wheatstone Bridge
For a certain adjustment of Q, VBD = 0, therefore no current flows through the galvanometer.
→ VB = VD or VAB = VAD
→ l1.P = l2.R
Alt txt : wheatstone bridge
Likewise, VBC = VDC Þ l1.Q = l2.S
Dividing (1) by (2), we get, P / Q = R / S
What’s the effective resistance of the circuits shown in the adjacent figure?
Alt txt : effective resistance of the circuits shown
(a) It is a Wheatstone bridge that is balanced. Hence, the central resistance labeled ‘C’ can be assumed as ineffective.
→ Req = R.
(b) The resistance R is in parallel with a balanced Wheatstone bridge.
→ Req = R.R / R + R = R / 2