If all of the current leaving one resistor enters another resistor, the two resistors are in series. If all of the voltage across one resistor is across another resistor, the two resistors are in parallel. Two resistors on the same path are in series.
In a parallel circuit, charge divides up into separate branches such that there can be more current in one branch than there is in another. The current outside the branches is the same as the sum of the current in the individual branches. It is still the same amount of current, only split up into more than one pathway.
A parallel circuit comprises branches so that the current divides and only part of it flows through any branch. The voltage, or potential difference, across each branch of a parallel circuit is the same, but the currents may vary.
A parallel circuit is a closed circuit in which the current divides into two or more paths before recombining to complete the circuit. Each load connected in a separate path receives the full circuit voltage, and the total circuit current is equal to the sum of the individual branch currents.
A third type of circuit involves the dual use of series and parallel connections in a circuit; such circuits are referred to as compound circuits or combination circuits. The circuit depicted at the right is an example of the use of both series and parallel connections within the same circuit.
In summary, a series circuit is defined as having only one path through which current can flow. From this definition, three rules of series circuits follow: all components share the same current; resistances add to equal a larger, total resistance; and voltage drops add to equal a larger, total voltage.
A disadvantage of parallel circuits is that they require more wiring. Additionally, the voltage can't be increased in a parallel circuit without decreasing the resistance in the circuit.
The supply voltage is shared between components in a series circuit. The sum of the voltages across components in series is equal to the voltage of the supply. This means that if two identical components are connected in series, the supply voltage divides equally across them.
Resistors in parallelIn a parallel circuit, the net resistance decreases as more components are added, because there are more paths for the current to pass through. The two resistors have the same potential difference across them. The current through them will be different if they have different resistances.
In a series circuit the current is the same at any particular point on the circuit. The voltage in a series circuit, however, does not remain constant. 4. The voltage drops across each resistor.
Once the charges get out of the resistors, the electric field of the battery is enough to drive them mad (as the wire has relatively lower resistance). And, the charges get back their energy once again. This is the reason why we say voltage is the same in parallel circuits3. The reason is that charge is conserved.
When resistors are connected in parallel, more current flows from the source than would flow for any of them individually, so the total resistance is lower. Current I for each device is much larger than for the same devices connected in series (see the previous example).
Key Points
Each resistor in parallel has the same voltage of the source applied to it (voltage is constant in a parallel circuit). Parallel resistors do not each get the total current; they divide it (current is dependent on the value of each resistor and the number of total resistors in a circuit).When the bulbs are in parallel, each bulb sees the full voltage V so P=V2R. Since a bulb glows brighter when it gets more power the ones in parallel will glow brighter. See, the parallel combination of resistors reduces the effective resistance of the circuit.
If the light bulbs are connected in parallel, the current flowing through the light bulbs combine to form the current flowing in the battery, while the voltage drop is 6.0 V across each bulb and they all glow. When a bulb in a series circuit blows off, the power supply to all other bulbs is cut off.
Advantages of series combination:
Cells connected in series give a greater resultant voltage than individual cells.Voltage increases if the number of cells increases. Series circuits do not overheat easily.An example of a parallel circuit is the wiring system of a house. A single electric power source supplies all the lights and appliances with the same voltage. If one of the lights burns out, current can still flow through the rest of the lights and appliances.
The series circuit is cheaper to make. The parallel circuits bulbs are brighter. The parallel circuits are longer lasting.
Difference between series and parallel circuit
| Series Circuit | Parallel Circuit |
|---|
| A circuit is said to be a series circuit when the flow of current is the same throughout all the components in the circuit. | A parallel circuit refers to a circuit with two or more two paths for the current to flow. |
Complete answer:
| Advantages | Disadvantages |
|---|
| We can connect or disconnect a new electric appliance in the circuit without affecting the other components in the circuit. | We cannot meet the requirement when the exact same amount of current is required to pass through the element. |
Both can be as safe as one another. The supply voltage is the deciding factor. The components connected in parallel circuits operate at different voltages.
There is no division of voltage among the appliances when connected in parallel. The potential difference across each appliance is equal to the supplied voltage. The total effective resistance of the circuit can be reduced by connecting electrical appliances in parallel.
What happens if one device in a parallel circuit fails? A break in any one path does not interrupt the flow of current in the other paths. The reciprocal of the total resistance is equal to the sum of the reciprocals of individual resistance.
In a series circuit, every device must function for the circuit to be complete. If one bulb burns out in a series circuit, the entire circuit is broken. In parallel circuits, each light bulb has its own circuit, so all but one light could be burned out, and the last one will still function.
Chapter 5 - Series And Parallel Circuits
- Voltage: Voltage is equal across all components in a parallel circuit.
- Current: The total circuit current is equal to the sum of the individual branch currents.
- Resistance: Individual resistances diminish to equal a smaller total resistance rather than add to make the total.
