Pronunciation: diàn lù
English: circuit/electric circuit
Explanation: (1) A pathway or group of interconnecting pathways that can carry current. Circuits through which direct current passes are called "direct current circuits"; circuits through which alternating current passes are called "alternating current circuits"
(2) An arrangement of one or more complete, closed paths for the flow of electrons
(3) A defined portion of a circuit
English: circuit/electric circuit
Explanation: (1) A pathway or group of interconnecting pathways capable of carrying current. prescribed portion
(4) A complete pathway for a current including any displacement current
(5) A combination of electronic components
Academic Explanation
An electrical circuit is a pathway through which a current flows.
Circuits (English: Electrical circuit) or electronic circuits, are electrical devices and components, linked in a certain way to provide a path for the flow of electric charges in general, also called electronic circuits or electrical circuits, referred to as networks or loops. Such as resistors, capacitors, inductors, diodes, transistors and switches, etc., constitute the network.
The size of the circuits can vary greatly, from small integrated circuits on silicon wafers to large high and low voltage power transmission networks.
According to the different signals processed, electronic circuits can be divided into analog and digital circuits.
Analog circuits
- The continuity of the physical and natural quantities generated by nature, the continuity of the physical and natural quantities are converted into a continuity of the electrical signals, the operation of the continuity of the electrical signals of the circuits known as analog circuits.
- Analog circuits process the continuity of voltage and current of electrical signals.
The most typical applications of analog circuits include: amplifying circuits, oscillating circuits, linear arithmetic circuits (addition, subtraction, multiplication, division, differentiation and integration circuits). Operate continuum electrical signals.
Digital circuits
- Also known as logic circuits
- Circuits that convert continuous electrical signals into discontinuous quantized electrical signals and operate on discontinuous quantized electrical signals are called digital circuits.
- In digital circuits, the magnitude of the signal is a discontinuous and quantized voltage state.
Mostly Boolean algebraic logic circuits are used to process the quantized signal. Typical digital circuits are, oscillators, registers, adders, subtractors, etc.. Operational discontinuity quantized electrical signals.
Multilayer circuits
-Multilayer circuits are also called ICs.
- Semiconductor circuits, which are designed by applying an integrated circuit design program (IC design) to design general circuits into semiconducting materials (usually silicon chips), are called multilayer circuits.
-The use of semiconductor technology to create an integrated circuit (IC).
Circuit Composition
A circuit consists of four major parts: power supply, load, connecting wires and auxiliary equipment. Since circuits in practice are complex, in order to make it easier to analyze the essence of a circuit, it is common to use symbols to represent the actual components of the circuit and their connecting wires in what is known as a circuit diagram. Among them, the wire and auxiliary equipment collectively known as the intermediate link.
1. Power supply
A power supply is a device that provides electrical energy. The function of the power supply is to convert non-electrical energy into electrical energy. For example, the battery is the chemical energy into electrical energy; generator is the mechanical energy into electrical energy. Because there are many types of non-electrical energy, there are many ways to convert into electrical energy, so there are many types of practical power supplies, and the most commonly used power supplies are dry cell batteries, storage batteries and generators.
2. Load
Various devices that use electrical energy in the circuit are collectively referred to as loads. The function of the load is to convert electrical energy into other forms of energy. For example, the electric furnace converts electrical energy into thermal energy; electric motors convert electrical energy into mechanical energy, and so on. Usually used lighting, household appliances, machine tools, etc. can be called load.
3. Wire
Connection wire is used to connect the power supply, load and other auxiliary equipment into a closed loop, plays a role in the transmission of electrical energy.
4. Auxiliary equipment
Auxiliary equipment is used to realize the control of the circuit, distribution, protection and measurement. Auxiliary equipment includes a variety of switches, fuses and measuring instruments.
Physical quantities of circuits
The role of circuits is to carry out the mutual conversion between electrical energy and other forms of energy. Therefore, a number of physical quantities are used to represent the state of the circuit and the interrelationship of energy conversion between its parts.
(1) current
Current has two meanings in practical terms: first, the current represents a physical phenomenon, that is, the regular movement of electric charge to form a current. Second, originally, the size of the current with the current intensity to indicate that the current intensity is the amount of charge through the cross-sectional area of the conductor in a unit of time, its unit is the ampere (ku/sec), referred to as ampere, with a capital letter A said. But the current intensity usually people more short for current. So the current also represents a physical quantity, which is the second meaning of current.
The true direction and positive direction of the current are two different concepts and should not be confused.
It is customary to always take the direction of the positive charge movement, as the direction of the current, which is the actual direction of the current or the real direction, which is objective, can not be chosen arbitrarily, in a simple circuit, the actual direction of the current can be easily determined by the polarity of the power supply or voltage.
However, in complex DC circuits, the real direction of the current in a section of the circuit is difficult to determine in advance, in AC circuits, the size and direction of the current is changing with time. At this point, in order to analyze and calculate the needs of the circuit, the introduction of the concept of current reference direction, the reference direction is also called the assumption of positive direction, referred to as positive direction.
The so-called positive direction, that is, in a section of the circuit, in the current in two possible real direction, arbitrarily choose a reference direction (that is, the assumed positive direction). When the actual current direction is the same as the assumed positive direction, the current is positive; when the actual current direction is opposite to the assumed positive direction, the current is negative.
Put another way, for the same circuit, it can be represented differently depending on the positive direction chosen; it can be positive or negative. In particular, once the positive direction of the current in the circuit has been determined, it must be used throughout the analysis and calculation process, and no further changes are allowed.
(2) voltage and potential
Numerically, the voltage between the two points AB is the force of the electric field to the unit of positive charge from point A to point B of the work done; and the potential of a point in the electric field is equal to the force of the electric field will be the unit of positive charge from the point of the work done to move to the reference point. Comparing the concepts of voltage and potential shows that the potential at a point in an electric field is the voltage between that point and the reference point, and that potential is a special form of voltage. For potential, the reference point is crucial. In the same circuit, elected different reference point, the same point of the potential value is different.
In principle, the reference point can be chosen arbitrarily. In the field of electrical engineering, it is common to select the grounding point in the circuit as the reference point, and in electronic circuits, the chassis is often taken as the reference point.
In practice, only know the voltage between the two points is often not enough, but also requires to know which point in the two points of high potential, which point is low. For example, for the semiconductor diode, and its anode potential is higher than the cathode potential before conduction; for DC motors, the winding ends of the potential is different, the direction of rotation of the motor may be different. Due to the need for practical use, we are required to introduce the polarity of the voltage, that is, the direction of the problem.
(3) electric potential
(4) electric power
(5) voltage and current correlation positive direction
circuit state
1. open circuit Also called a broken circuit, because of interruption of one of the circuit due to the resistance of the interruption is too large, the current can not be normal through, resulting in zero current in the circuit, the interruption of the voltage at both ends of the point of the voltage for the power supply, generally no damage to the circuit. The voltage at both ends of the interruption point is the supply voltage, generally no damage to the circuit.
2. Short-circuit power supply is not through the load and directly connected by the wire into a closed loop.
3. Normal Load Conditions
Circuit Laws
All circuits follow some basic circuit laws.
- Kirchhoff's current law: The sum of the currents flowing into a node equals the sum of the currents flowing out of the node.
- Kirchhoff's voltage law: the sum of the loop voltages is zero.
- Ohm's law: the voltage across a linear element, such as a resistor, is equal to the product of the resistance of the element and the current flowing through it.
- Norton's Theorem: Any two-terminal network consisting of a voltage source and a resistor can always be equated to a parallel network of an ideal current source and a resistor.
- Davening's theorem: Any two-terminal network consisting of a voltage source and a resistor can always be equated to a series network of an ideal voltage source and a resistor.
Analyzing circuits that contain nonlinear devices requires some more complex laws. In real-world circuit design, circuit analysis is more often done through computer analysis simulations.
Circuit power
When all circuits work, every component or circuit has a working use of energy, or electrical energy, and the working use of electrical energy in all circuits is called circuit power.
The power of a circuit or circuit element is defined as: Power = Voltage * Current (P = I * V).
In nature, energy is not destroyed, there is a law of indestructibility of energy.
Total circuit power = circuit power + power of each circuit element. For example: Power (I*V) = Circuit (I*V) + Components (I*V)
The energy in the circuit will sometimes become heat or radiant energy ... and other energy into the air, which is the reason why the circuit or the circuit components will be heated, will not be all the formation of electricity in the circuit, according to the indestructibility of the total energy = electrical energy + thermal energy + radiant energy + other energy.
Types of circuits
- Power supply circuits: the power supply required to generate various electronic circuits.
-Electronic circuit: also known as electrical circuit.
Types of frequencies
- Base frequency circuits, base frequency, low frequency, using base frequency components.
-High-frequency circuits, high-frequency, high-frequency, use high-frequency components.
-Base frequency, high frequency hybrid circuits
Types of components
-Passive components: such as resistors, capacitors, inductors, diodes, ..., etc., there are divided into base frequency passive components, high frequency passive components.
-Active components: such as transistors, microprocessors ... and so on, there are base-frequency active components, high-frequency active components.
Types of applications
Microprocessor circuits: Also known as microcontroller circuits, they form the basis for computers, game consoles, (player video, audio), various home appliances, mice, keyboards, touch controls, etc.
The microprocessor circuits are also known as microcontroller circuits.
Computer circuits: Microprocessor circuits are advanced circuits that form desktop computers, notebook computers, handheld computers, industrial computers, and various other computers.
Communication circuits: Forming telephones, cell phones, wired networks, wired transmissions, wireless networks, wireless transmissions, optical communications, infrared, fiber optic, microwave communications, satellite communications, and so on.
Display circuits: Formation of the screen, TV, meters!
Display circuits: Forming screens, TVs, meters, etc.
Optical circuits: such as solar circuits.
Motor circuits: Often used in large power supply devices, such as electric power equipment, transportation equipment, medical equipment, industrial equipment...etc..
Motor circuits.