Help is available everywhere. This is the unit of electrical current flow. The rate at which current flows past a given point. An attenuator is a passive network comprising usually, but not always, resistors that reduce the power or voltage level of a signal without introducing significant distortion. This is a relative power unit.
Direct current is where at all times the voltage polarity remains constant.
D.C. may however, particularly where it is rectified from mains a.c., contain residual a.c. superimposed or part of the voltage. This is often referred to as mains hum. A means or circuit designed to convert amplified R.F. energy into recovered audio which contains the desired intelligence. A dipole is an antenna. It is a fundamental form of antenna consisting of a single wire whose length is approximately equal to half the transmitting wavelength.