Download Q1 A time varying current can be expressed as follows

Tutorial 6
Problem 1
Explain the term time constant in connection with an inductive circuit.
A coil having a resistance of 25  and inductance of 2.5 H is connected across a 50 V
d.c. supply. Determine
(i)
the initial rate of growth of the current;
(ii)
the value of the current after 0.10 s; and
(iii)
the time required for the current to grow to 1.8 A.
Problem 2
The Figure below shows an AC quantity. From the graph determine the following
quantities: the peak value, the peak-to-peak value, the r.m.s value, the frequency, the
angular frequency, the period, the instantaneous value at time t = 0.015.
Problem 3
(a) State what is meant by the root mean square value of an alternating voltage and
explain why the r.m.s. value is usually more important than either the maximum or the
mean value.
(b) Calculate the mean voltage over (i) one complete cycle (ii) half a cycle of alternating
voltage
v  Vm Sint ,  is the angular frequency in rads/s.