15-12-2012, 05:05 PM
VERIFICATION OF NETWORK THEOREMS
VERIFICATION OF NETWORK.pdf (Size: 117.44 KB / Downloads: 83)
PROCEDURE:
1. Keep all the rheostats close to their maximum resistance values.
2. Close the switch S1 to position ‘aa’ and S2 to ‘cc’. Observe the load (26 ohm rheostat) current (IL) and terminal voltage (VL) readings. Then the value of load resistance RL=VL/IL.
3. Disconnect the load by opening the switch S2 and read the open circuit voltage (or Thevenin equivalent voltage) VTH.
4. Next, to compute the Thevenin equivalent resistance (RTH) of the network as seen from the load terminals:
i) Replace the 220V source by a short by closing S1 to ‘bb’.
ii) Apply 110V at the output terminals by closingS2 to ‘dd’. Read the
voltmeter (V) and ammeter(I) and get RTH= V/I.
5. Now compute the load current applying Thevenin’s theorem as
IL=VTH/(RTH+RL).
6. Compare the above computed load current with its observed value in step (2) and verify the Theorem.
7. Adjust all the rheostats to new settings and repeat from step (2) to step (6) for at least six sets of readings without exceeding rated current in any element.