What is an Electric Circuit?
The electrical circuit or the electric circuit is an interconnection of electrical components to perform a specific function. These circuits use two types of power, one is alternating current and the other is direct current. The AC current is generated by power stations and is used for large devices whereas the DC current is used for batteries, machines, and electrical appliances.
When this current is flowing through the devices, the power may increase or decrease suddenly, when the power has decreased the effect that occurs to the device is less. Whereas when the power is very high and if it increases more than the threshold voltage then the damage occurs to the whole components used in the circuit, so in order to protect that circuit breakers or fuses are arranged in series with the components to prevent the damage to the whole circuit. Let us see the basic electronic components symbols.
Electrical Circuit Symbols
An electric circuit is a closed-loop circuit that provides the path for the flow of electric current. A pictogram that is used to represent the various electronic devices such as wires, resistors, capacitors, inductors, conductors, etc is known as electrical circuit symbols.
There are certain standards to be followed to represent the symbols. The recently used graphic symbols for the electric circuit are made according to national and international standards.
British standard that is BS 3939, this can also be represented as IEC 60617.
For the ladder logic symbols, there is a British standard IEC 61131 - 3.
NMTBA whose expansion is National Machine Tool Builders Association has approved the symbols of the Joint Industrial Council (JIC).
The graphic symbols used for logic functions in digital electronics are approved by the IEEE std 91/91 a.
Grounds: Triangle is the symbol usually used for the grounds.
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Sources: The main source is the batteries, with single or multi-cell.
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Resistors: For many types of resistors, rheostat or potentiometer symbols are used.
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Capacitor:
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Diode: Triangle is the symbol used and these can be drawn in multiple ways.
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Inductors:
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Transistors:
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Transformer:
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Switch:
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Diagram of an Electric Circuit
The graphical representation of the electric circuit is called a circuit diagram. Using the standard symbols the interconnections of the components are observed in this circuit diagram. It is not universal convection that the components are to be placed in a manner, that is from the left to right or top to bottom. This will help you to understand all circuit symbols.
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Example: In the case of a radio receiver, it starts from the left side of the page with the antenna input, and ends at the right side of the page with a loudspeaker. At each stage, the positive power connections are made to the top of the page and the negative supplies and grounds are shown to the bottom. The details for the construction of circuit diagrams are provided in the international standard IEC 61082 - 1 is used in the electrotechnology.
Types of Electric Circuit:
Now we have got to know what is an electric circuit, now let us see the different types of electric circuits. There are four different types of circuits:
Open Circuit: The circuit is said to be open when there is no flow of electricity in the circuit. The circuit might be open when the circuit is in switch-off condition or in the presence of a faulty wire or component.
Closed-Circuit: The circuit is said to be closed when the flow of electricity takes place. The current flow happens where the switch is on and the amount of current flow depends on the load.
Short Circuit: The points present in the voltage source in a circuit is connected to the other points then the circuit is said to be a short circuit. During this condition, the maximum current flows in the circuit. Due to the short in the load, the conducting electrical wires get joint.
Parallel Circuit: When two or more loads are connected in the parallel form then the circuit is said to be a parallel circuit. Here supplied load is equally distributed to all the loads present in the circuit. In this parallel circuit if any one of the loads or bulb present gets fuse, then the remaining ones will work.
Series Circuit: When two or more loads are connected in the series form then the circuit is said to be a series circuit. As these are connected in series that is one end of the load is connected to the opposite end of the other load, when any of these gets fuse then the remaining loads also will stop functioning.
Conclusion:
Electric circuits and their circuit components are used in our day-to-day life. In fact without them the present generation people are not able to do a single work. The sources supplied to these circuits is either dependent or independent. The independent source will maintain the same value of the voltage supply irrespective of the type of voltage that is being supplied. Whereas the dependent source voltage varies depending on the type of source it is being applied.
Refer to the basic electronic components and their functions ppt to have more grip on the concept.
FAQs on Electric Circuit and Electrical Symbols
1. What is an electric circuit in simple terms?
An electric circuit is a complete, closed path that allows electricity to flow. Think of it as a racetrack for electric current, which starts from a power source like a battery, moves through components such as a bulb or a motor, and then returns to the source to complete the loop.
2. What are electrical symbols and why are they important in a circuit diagram?
Electrical symbols, also known as schematic symbols, are standardised pictures used to represent different electronic components. They are important because they create a universal language for drawing circuit diagrams, allowing anyone to understand the layout and function of a circuit regardless of the physical appearance or brand of the components.
3. What are the essential components of a simple electric circuit?
A basic, functional electric circuit requires at least four essential components:
- An energy source (like a battery or cell) to provide voltage.
- A conductor (like copper wires) to form the path for the current.
- A load (like a light bulb) that consumes the electrical energy.
- A switch to control the flow of current by opening or closing the circuit's path.
4. What does the symbol of a rectangle or a zigzag line represent in a circuit diagram?
In a circuit diagram, both a rectangle and a zigzag line are standard symbols used to represent a resistor. A resistor is a component specifically designed to control, limit, or impede the flow of electric current within a circuit.
5. How are the 'ON' and 'OFF' positions of a switch shown using symbols?
The symbol for a switch shows a break in the wire with a small lever.
- An 'ON' or closed switch is depicted with the lever connecting the two points, showing a continuous path for the current to flow.
- An 'OFF' or open switch is depicted with the lever lifted away, showing a visible gap that indicates the path is broken and current cannot flow.
6. Why must an electric circuit be a closed loop to function?
An electric circuit must be a closed loop because electric current requires a continuous and uninterrupted path to travel from the high-potential (positive) terminal of the power source to the low-potential (negative) terminal. If there is any break in this path, it becomes an open circuit, the flow of electrons stops, and the device connected to it will not work.
7. What is the key difference between an open circuit and a short circuit?
An open circuit has an intentional break (like an open switch) that stops current flow, rendering the circuit inactive but safe. In contrast, a short circuit is an unintended, low-resistance path that bypasses the intended load (like a bulb). This causes an excessive amount of current to flow, which is dangerous as it can lead to overheating, equipment damage, and fire.
8. How do the symbols for a single cell and a battery differ?
The symbols are related but distinct. A single electric cell is represented by one pair of parallel lines: one long (positive terminal) and one short, thick line (negative terminal). A battery, which is a collection of cells, is represented by a series of two or more of these cell symbols connected together, indicating a higher combined voltage.
9. Why are an ammeter and a voltmeter connected differently in a circuit?
Their connection methods differ based on what they measure.
- An ammeter (symbol 'A' in a circle) measures the current flowing *through* the circuit, so it must be connected in series, making it part of the main path.
- A voltmeter (symbol 'V' in a circle) measures the voltage *across* a component, so it is connected in parallel, creating a separate branch around the component being measured.
10. Can you build a working circuit without a load, like a lightbulb?
Connecting a power source directly to wires without a load (like a resistor or a bulb) is extremely dangerous and should never be done. This creates a short circuit. The absence of a load means there is almost no resistance to oppose the current, causing it to rise to a very high level. This will rapidly drain and damage the battery and can cause the wires to overheat and potentially start a fire.
