ABSTRACT
INTRODUCTION One of the typical signals used in electrical engineering is the sinusoidal signal. The electric power, distributed in North America, has sinusoidal form and the current changes its direction periodically 60 times per second. Europe uses alternating current distribution as well, but the frequency is 50 Hz. Unless there is power failure, the system is connected all the time. If you turn on the light or connect an electric motor, you disturb the system a little but in general we can say that the system is not changing and is, as we say, in a steady state. Occasionally, there may be power failure and then other processes take place; we call them transients.
