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 commonly 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
The electric power P is equal to the energy consumption E divided by the consumption time t\cite{meade2002foundations}
$$P =\frac Et$$
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].
@ -13,13 +13,13 @@ Ohm's Law deals with the relationship between voltage and current in an ideal co
$$I =\frac U R $$
where I is the current expressed in Amperes [A], V is the voltage, bearing the Volt units [V] and R is the electrical resistance in ohms [$\Omega$].
The Ohms's law can be further expanded, to get these three quantities in relationship with \textbf{power}, such as
The Ohms's law can be further expanded\cite{beaty1998electric}, to get these three quantities in relationship with \textbf{power}, such as
$$P = I \cdot V = I^2\cdot R =\frac{U^2}R$$
\subsection{Direct current (DC) circuits}
Generally, Ohm's law is used on \gls{dc} circuits. A DC voltage or current has a fixed magnitude (amplitude) and a definite direction associated with it. Both DC currents and voltages are produced by power supplies, batteries, dynamos and solar cells to name a few.
We also know that DC power supplies do not change their value with regards to time, they are a constant value flowing in a continuous steady state direction. In other words, DC maintains the same value for all times and a constant uni-directional DC supply never changes or becomes negative unless its connections are physically reversed.
We also know that DC power supplies do not change their value with regards to time\cite{herman2012direct}, they are a constant value flowing in a continuous steady state direction. In other words, DC maintains the same value for all times and a constant uni-directional DC supply never changes or becomes negative unless its connections are physically reversed.
\subsection{Waveforms and alternating current (AC) circuits}
An alternating function or \gls{ac} waveform on the other hand is defined as one that varies in both magnitude and direction in more or less an even manner with respect to time making it a “bi-directional” waveform \cite{whitaker2006ac}. An AC function can represent either a power source or a signal source with the shape of an AC waveform generally following that of a mathematical sinusoid as defined by
Peter Babič
8 years ago