What are $A.C.$ signals?

(N/A) An $A.C.$ (Alternating Current) signal is an electric current or voltage that periodically reverses its direction and changes its magnitude continuously with time.
Unlike $D.C.$ (Direct Current),which flows in a single direction,$A.C.$ follows a sinusoidal waveform in most power applications.
The mathematical expression for an $A.C.$ voltage is typically given by $V(t) = V_m \sin(\omega t + \phi)$,where $V_m$ is the peak voltage,$\omega$ is the angular frequency,and $\phi$ is the phase constant.
$A.C.$ is widely used for power distribution because its voltage can be easily stepped up or down using transformers.