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Q15. For the Network shown in Fig Q1 calculate EACH of the following:

(a) The current in the indicating meter.

(b) The value to which the 1 kΩ resistor must be changed to make the current in the meter lmA in the direction found in Q1 (a).

Q6. A circuit comprises a resistor of 800 Q in series with a non-linear element whose characteristic is given by I = 0.5V^3/2 where I is in mA and V is in volts. The circuit is connected to a 12 V d.c. supply.

Determine EACH of the following:

(a) The circuit current;

(b) The voltage across the non-linear element;

(c) The value to which the 800 Q resistor must be changed to make the circuit current 10 mA.

Q3. A power silicon transistor with the characteristics given in Worksheet Q3 is operated from

a 16V d.c. supply. The operating (quatient’s) point is  = 40 mA and  = 2 mA.

Determine EACH of the following:

(a) Draw the load line on the characteristics;

(b) (i) The value of the collector load resistance;

(ii) The peak to peak variation in collector if a signal of  20 mA is applied to the base;

(iii) The corresponding variation in collector current',

(iv) The power dissipated in the transistor due to this signal

Q8. An a.c. series circuit consists of four elements as shown in Fig Q4. The power dissipated in the 50Ω resistor is 200 W and the volt drops across the various parts of the circuit are as shown.

Calculate EACH of the following:

(a) The values of C and L;

(b) The overall power factor of the circuit;

(c) The kVAR for the inductance.

Q6.  A 440 V/110 V single phase transformer is rated at 40 kV A full load output. The iron loss is 3 kW and it operates at maximum efficiency when delivering 80% full load,

Calculate EACH of the following:

(a) The full load copper loss;

(b) The full load efficiency at O .9 power factor;

(c) The efficiency at 80% full load and unity power factor.