Functions of net
1) Function of net:
It is the relationship between the transformed one of the
which had effect u(t) to one determined cause e(t) and the transformed
one of this last one. In formulas 
is had.
2) impulsive Answer:
Draft of the consequent effect to the application of an impulse, is particularly important because the transformed one of the impulse is 1 and therefore the impulsive answer corresponds to the antitransformed one of the function of F(s) net which depends on the circuit.
3) Convoluzione:
In order to obtain the answer to it marks them of income is not necessary to go and to return in the dominion of Laplace, enough to observe that the antitransformed one of the two product transformed is equal to the product of convoluzione of theirs originates them.
The convoluzione is described from the integral 
Where h(t) the antitransformed one of the net function is the impulsive answer that is.
4) Characteristics of a function e(t) affinchè can approximate the impulse:
It must satisfy the two following property:
to) It must be various from zero solo in intervallo [ the 0,q]
b) For 0 < t < q the impulsive answer must be substantially constant h(t-t) @ h(t).
is had that therefore only differs
from the impulsive answer for the supplied amplitude of the integral.
Such approximation in the practical one is more than sufficient.
5) stable Circuit:
A circuit is stable if all the possible impulsive answers stretch to zero to growing of the time.
6) When a impulsive answer stretches to 0 to growing of the time:
When the transfer function possesses all the poles in the left semiplan.
7) When a impulsive answer is limited to growing of the time:
When the transfer function possesses of the simple poles on the imaginary axis.
8) real Inductance and its stiffness:
The real inductance previews a resistore in series to the ideal inductance, that determines an energy dissipation that therefore moves the pole from the origin carrying it in the semiplan of stability. The stiffness of the real inductance is
.
9) real Condenser and its equation of Laplace:
The real condenser previews a resistore in parallel to the ideal condenser, that determines an energy dissipation that therefore moves the pole from the origin carrying it in the semiplan of stability. The admittance of the real condenser is
.
10) Demonstrate that a circuit with real L and C has the poles in the left semiplan and therefore is stable:
Once written 
e
the hypothesis of uniform distribution
of the losses that is 
and pone is made s
d = p then has ZL=
Lp e YC= Cp
therefore behaves as ideal members and has the poles on the imaginary
axis but d>0 allora s = p-d < p therefore is in the
semiplan of stability.
11) free Answer:
It is the answer of the system when to it some external generator is not applied but the conditions only begin them.
12) forced Answer:
It is the answer of the system when to it they are applies the external generators to you but the conditions begin them are null.