AC Circuits and Kirchhoff’s law
AC Circuits and Kirchhoff’s law are explained
AC Circuits
An alternating current (AC) is an electrical current, where the magnitude of the current varies in a cyclical form, as opposed to direct current, where the polarity of the current stays constant.
The usual waveform of an AC circuit is generally that of a sine wave, as this results in the most efficient transmission of energy.
However in certain applications different waveforms are used, such as triangular or square waves
Introduction:
Used generically, AC refers to the form in which electricity is delivered to businesses and residences.
However, audio and radio signals carried on electrical wire are also examples of alternating current.
In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.
Kirchhoff’s law:
There are Kirchhoff’s Current Law and Kirchhoff’s Voltage Law.
Kirchhoff’s Current Law:
First law (Current law or Point law): Statement:
The sum of the currents flowing towards any junction in an electric circuit equal to the sum of currents flowing away from the junction.
Kirchhoff’s Current law can be stated in words as the sum of all currents flowing into a node is zero.
Conversely, the sum of all currents leaving a node must be zero. As the image below demonstrates, the sum of currents Ib, Ic, and Id, must equal the total current in Ia.
Current flows through wires much like water flows through pipes.
If you have a definite amount of water entering a closed pipe system, the amount of water that enters the system must equal the amount of water that exists the system.
The number of branching pipes does not change the net volume of water (or current in our case) in the system.
Kirchhoff’s Voltage Law:
Second law (voltage law or Mesh law): Statement:
In any closed circuit or mesh, the algebraic sum of all the electromotive forces and the voltage drops is equal to zero.
Kirchhoff’s voltage law can be stated in words as the sum of all voltage drops and rises in a closed loop equals zero.
As the image below demonstrates, loop 1 and loop 2 are both closed loops within the circuit.
The sum of all voltage drops and rises around loop 1 equals zero, and the sum of all voltage drops and rises in loop 2 must also equal zero.
A closed loop can be defined as any path in which the originating point in the loop is also the ending point for the loop.
No matter how the loop is defined or drawn, the sum of the voltages in the loop must be zero.
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