Twelfth class, The Power II

After the introductory class of the previous day, we still focus on the topic of the electrical power. We have started with some easy examples of calculating powers, as a refreshment of the past lesson. Then, we showed that, in fact, the expression of the power is one half by the amplitude of the signal squared by the real part of the afitance. So, from now on, we have to watch out in case we are given an impedance as a fraction, where some calculus will be required. 

As we continued with more examples of different signal waves (triangular, squared...) we have been introduced to two new units of power: the decibels (dB) and the decibels referenced to one miliwatt (dBm). The decibels result of the following expression: 10*log(PL/Pin). This way, a very wide range of powers is framed into a less extend scale. For instance,  while the value 2 of PL/Pin equals to 3, the value 1000 equals to 30, proving the effectivity of the decibel scale.

Also, the dBm have its expression: 10*log (P/1mW), creating this way a more compressed scale too.  To finish the class we did an example in which the input power and the power consumed by a resistance RL were directly related by the following expression: 

PL dbm = G db + Pin dBm