1. A multistage amplifier achieves greater voltage and power gain by using multiple amplification stages connected in cascade. The overall voltage gain is equal to the product of the individual stage gains. 2. Gain is often expressed in decibels (dB) which allows both small and large quantities to be conveniently represented on a logarithmic scale corresponding to human perception. The overall multistage amplifier gain in dB is the sum of the individual stage gains in dB. 3. Common types of coupling between stages include RC coupling using capacitors, direct coupling without coupling elements, and transformer coupling. RC coupling is inexpensive but limits low frequency response while direct coupling can amplify low frequencies without coupling elements.