Describe briefly how the bridge would be used to determine the value of the resistor, X .

1. Figure 11.52 shows a Wheatstone-bridge circuit. The ratio arms P and Q can each be set at 10, 100, 1000 or 10 000 and the variable resistor can be varied from 1 to 10 000 in steps of 1 _.

 

(a) Describe briefly how the bridge would be used to determine the value of the resistor, .

(b) Suggest values of Pand if the bridge is at balance and the resistor is 2.864 _.

2. A slide-wire bridge has a wire 1mlong and is arranged as shown in Figure 11.26. What is the value of the unknown resistor when the value of the known resistor and the distance of the slider from the left-hand end of the wire for balance, are, respectively

(a) 10 _, 27 cm (b) 2 _, 68 cm (c) 60 _, 42 cm

 

find the cost of your paper

Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator

1. (a) Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator: (i) series-connected, (ii) shunt-connected and (iii) compound-connected.   (b) State one purpose for which….

what happens if the resistance in series with the shunt field of a DC motor is increased in value

1. Sparking at the trailing edges of the brushes in a DC machine is usually prevented by fitting   (a) copper gauze brushes (b) a compensating winding (c) a compound….

Calculate the synchronous speed of a 10-pole three-phase machine connected to a 50 Hz supply.

1. The generator characteristic shown in Figure 9.28 is for a   (a) shunt machine (b) series machine (c) differentially compounded machine (d) cumulatively compounded machine 2.The speed of a….