Find the equivalent star of the delta configuration shown in the following figure. <img src='./qimages/11883-1a.jpg'>

Also write the formula for converting star connection into equivalent delta.
What are the disadvantages of low power factor in A.C. circuits? How can power factor be improved?

2.(a) Using Thevenin's theorem, find the current flowing through the 1 ohm resistor. Also draw the Thevenin's equivalent circuit across the 1 ohm resistor clearly showing the open circuit voltage. <img src='./qimages/11883-2a.jpg'>
Derive the relation between line current and phase current, line voltage and phase voltage for a delta connected 3-phase network.

3.(a) What are instrument transformers Explain voltage and current measurement in a high voltage system with the help of instrument transformer, using connection diagrams.
Explain the various excitation schemes for D.C. motors by providing proper circuit connection diagrams.

4.(a) Explain various kinds of single-phase motors and their appropriate applications.
Explain the construction, working and application of a permanent magnet moving coil instrument.

5.(a) Give the circuit diagram of a Voltage Regulator with Current Booster and explain its operation.
Discuss the circuit, operation and principle of Peak Response type A.C. voltmeters.

6.(a) Discuss a basic Operational Amplifier and explain its various applications in short.
Give the circuit connections of a 4-bit up counter and a 4-bit down counter. Also give waveforms of each.

7.(a) Draw the architecture of 8085 microprocessor clearly naming its various blocks, inputs and outputs.
Draw the circuit of a partially decoded memory system and also draw the concerned memory map.