electric power as a physical quantity + resistive load

problemexpres.tex

@@ -162,8 +162,9 @@ Whole printed circuit board of TL-WR703N was remade by the GL.inet team to expos
 
 
 \newpage
-\section{Electrical Power Measurements}
-Measuring the power makes most sense on the customer appliances. The first reason is, that they generally consume power that is purchased on contract. The energetic company measures all the power used up by the end customer, but customer has no easy way to see how much and how \textit{effectively} is power used by the appliances. The second important reason is that the appliances has a standardised connector (plug) that is guaranteed to fit in all the area using it, which is not a case for example on battery powered devices (batteries has different sizes, connectors and general properties.
+\section{Electric power measurement}
+
+Measuring the electric power makes most sense on the customer appliances. The first reason is, that they generally consume power that is purchased on contract. The energetic company measures all the power used up by the end customer, but customer has no easy way to see how much and how \textit{effectively} is power used by the appliances. The second important reason is that the appliances has a standardised connector (plug) that is guaranteed to fit in all the area using it, which is not a case for example on battery powered devices (batteries has different sizes, connectors and general properties.
 
 When it comes to measuring the electrical power, the first and the most important thing to discuss is safety. Only after all the safety precautions had been made clear, the theory can be clarified and subsequently, the practice can be applied. The chapter focuses solely on the first two topics.
 
@@ -190,4 +191,22 @@ The appliances under test work on mains voltage. In Europe, the nominal voltage
 
 If not handled with care, operating or manipulating with voltage can cause permanent damage to appliance or health, or can cause fire or even death. Thus, respect, increased care and knowledge is necessary in all further practical steps involved.
 
+\subsection{Electric power as a physical quantity}
+In general physics terms, power is defined as the rate at which energy is transferred (or transformed).Electric energy in particular, begins as electric potential energy – what we lovingly refer to as voltage. When electrons flow through that potential energy, it turns into electric energy. In most useful circuits, that electric energy transforms into some other form of energy. Electric power is measured by combining both how much electric energy is transferred, and how fast that transfer happens.
+
+
+The electric power P is equal to the energy consumption E divided by the consumption time t
+$$P = \frac Et$$
+where P is the electric power in watt (W), E is the energy consumption in joule (J) and 
+t is the time in seconds (s).
+\subsubsection{In resistive circuits}
+In the case of resistive (Ohmic, or linear) loads, Joule's law can be combined with Ohm's law (V = I·R) to produce alternative expressions for the amount of power that is dissipated:
+$$P = IV = I^2R = \frac{V^2}R$$
+
+\subsubsection{In alternating current (AC) circuits}
+sfaf
+
+
+
+\subsection{Measuring electric power with a microcontroller}
 

tukethesis.tex

@@ -125,6 +125,7 @@ autora. Má byť taký informatívny, ako to povoľuje podstata práce. Text abs
 \klucoveslova{Optimalizácia, záverečná práca, písanie}
 
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