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Student R e sou r c e :
What is a Simple Circuit?
Simple Circuit
A simple circuit consists of three elements: a source of electricity (battery), a path or
conductor on which electricity flows (wire) and an electrical resistor (lamp) which is any
device that requires electricity to operate. The illustration below shows a simple circuit
containing a battery, two wires, and a low voltage light bulb. The flow of electricity is
caused by excess electrons on the negative end of the battery flowing toward the positive
end, or terminal, of the battery. When the circuit is complete, electrons flow from the
negative terminal through the wire conductor, then through the bulb (lighting it up), and
finally back to the positive terminal - in a continual flow.
Student R e sou r c e : What are Series and Parallel Circuits?
Series and parallel describes two different types of circuit arrangements. Each
arrangement provides a different way for electricity to flow throughout a circuit.
Series Circuits
In a series circuit, electricity has only one path on which to travel. In the example to the
right, two bulbs are powered by a battery in a series circuit design. Electricity flows from
the battery to each bulb, one at a time, in the order they are wired to the circuit. In this
case, because the electricity can only flow in one path, if one of the bulbs blew out, the
other bulb would not be able to light up because the flow of electric current would have
been interrupted. In the same way, if one bulb was unscrewed, the current flow to both
bulbs would be interrupted.
Parallel Circuits
In a parallel circuit, electricity has more than one path on which to travel. In the example
to the right, two bulbs are powered by a battery in a parallel circuit design. In this case,
because the electricity can flow in more than one path, if one of the bulbs blew out, the
other bulb would still be able to light up because the flow of electricity to the broken bulb
would not stop the flow of electricity to the good bulb. In the same way, if one bulb were
unscrewed, it would not prevent the other bulb from lighting up.
What About Resistance?
The flow of electricity depends on how much resistance is in the circuit. In our examples,
the bulbs provide resistance. In a series circuit, the resistance in the circuit equals the
total resistance of all the bulbs. The more bulbs in the circuit, the dimmer they will light.
In a parallel circuit, there are multiple paths through which current can flow, so the
resistance of the overall circuit is lower than it would be if only one path was available.
The lower resistance means that the current will be higher and the bulbs will burn
brighter compared to the same number of bulbs arranged in a series circuit.
What happens to the brightness of the bulbs in a series circuit when more bulbs are
added?
They get dimmer, since it is a series circuit, all bulbs are exposed to the same current,
and every bulb adds resistance (measured in ohms) reducing the amount of energy
each bulb has (measured in amperes) since the bulbs have less energy to use, they give
off less energy, resulting in a weaker light. (The potential difference of each bulb
decreases and as a result the light becomes less bright.)
In series each resistor, light bulb or motor, is said to share the voltage evenly
(assuming they have same resistance). For example if I have a 20V power source and
have currently 4 light bulbs of same resistance and voltage rating, they each have a
potential difference of 5V add another light bulb identical to the others and they each
gain a potential difference of 4V and add another again and it becomes 3.333V per
light.
Current is the same no matter where you measure it in the circuit but you may
decrease the current if you add more light bulbs only because of the extra resistance
being applied. This is due to Ohm's law that I=V/R -I is current -V is voltage -R is
resistance
Current plays no part in the brightness of the bulb, only voltage influences how bright
the light bulbs are and if its split more between extra light bulbs then they will become
duller.
If bulbs are connected to other bulbs just like in Christmas Light series, they get
dimmer.Why? On the other hand,if they are connected to other bulbs just like in a
parallel circuit as in household wiring,they stay as it is.Why?
The voltage doesn’t remain constant in series so the potential difference makes
them dimmer; in parallel circuits, the voltage remains constant.
understand if the battery arrangement to the circuits are in parallel there will be a lot
more volts going to the receiver (bulb or motot).
batteries wired in series will add their voltage together to provide energy to the
circuit. The available amperage remains constant (how long the energy lasts).
If you wired 8 batteries in a parallel arrangment, the available amperage (time
working) would increase, but you would only have the 6v (amount of one battery) as
the energy is pulled from one battery at a time until it is all used up.