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Parallel Circuits

A parallel circuit is one that has actually two or an ext paths for the power to flow, the loads are parallel to each other. If the tons in this circuit were light bulbs and one blew out, there is still existing flowing to the others since they space still in a straight path native the an unfavorable to optimistic terminals the the battery.



A Parallel circuit is one v several various paths because that the electricity to travel. It"s choose a flow that has actually been separated up into smaller streams, however, all the streams come earlier to the same point to form the river as soon as again.

The parallel circuit has very different features than a collection circuit. For one, the full resistance the a Parallel Circuit is no equal come the sum of the resistors (like in a series circuit). The total resistance in a parallel circuit is always less than any type of of the branch resistances. Adding much more parallel resistances come the paths causes the complete resistance in the circuit to decrease. As you add much more and much more branches to the circuit the full current will increase since Ohm"s law states that the lower the resistance, the greater the current.


BASIC rule

A Parallel circuit has specific characteristics and basic rules:

1. "A parallel circuit has two or much more paths for current to flow through."

Simply remember the PARALLEL method two courses up to hundreds of paths. The flow of electrical power is divided between each according to the resistance along each route.


2. "Voltage is the same throughout each component of the parallel circuit."

You might remember indigenous the last ar that the voltage drops across a resistor in series. No so with a parallel circuit. The voltage will certainly be the same almost everywhere in the circuit.


3. "The amount of the currents with each route is equal to the full current the flows native the source."

If one route is illustration 1 amp and also the other is illustration 1 amp climate the total is 2 amps at the source. If there are 4 branches in this exact same 2 amp circuit, then one path may draw 1/4A (.25A), the following 1/4A (.25), the following 1/2A (.5A) and also the critical 1A.

Don"t worry, the next preeminence will show you just how to number this out. Just remember for now that the branch currents need to be same to the source current.


4. "You deserve to find total RESISTANCE in a Parallel circuit v the following formula: 1/Rt = 1/R1 + 1/R2 + 1/R3 + ... "

Before we get into the calculations, remember what we stated at the start of this section: "The full resistance of a parallel circuit is not equal come the sum of the resistors (like in a series circuit).

We will usage a parallel circuit with 3 routes as an example (it can be 2, 4 or a 1000 resistors in parallel). The power source is giving 12 volts and the worth of the resistors space 5 Ohms, 5 Ohms and also 2 Ohms.

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Let"s summize this EXAMPLE:

Voltage = 12V R1 = 4 Ohm R2 = 4 Ohm R3 = 2 Ohm

Remember the "Rt" means Total resistance that the circuit. R1, R2, etc. Room Resistor one, Resistor two, etc.

Now we will use the formula over to this example:

1 — - = Rt

1 — - + R1 1 — - + R2 1 — - R3


1 — - = Rt

1 — - + 4 1 — - + 4 1 — - 2

It is easiest to readjust the fractions into decimal number (example 1 division by 4 equates to .25):

1/Rt = .25 + .25 + .5 1/Rt = 1

Now you have actually to remove the 1 ~ above the left next so...

Rt = 1/1 Rt = 1 Ohms

NOW, Let"s try a more complicated one:

Voltage = 12 Volts R1 = 10 Ohms R2 = 20 Ohms R3 = 10 Ohms R4 = 1 Ohms 1/Rt = 1/10 + 1/20 + 1/10 + 1/1 1/Rt = .1 + .05 + .1 + 1 1/Rt = 1.25 Rt = 1/1.25 = .8 Ohms

Before we move on come the last dominion here"s how easy the is to calculate the amperage with each course using OHM"S LAW.

In the example we see a 12 and also 24 ohm resistor in parallel through a 12 volt source. An initial we number out the total resistance that the circuit:

1/Rt = 1/12 + 1/24 Rt = 8 Ohms


Now that you recognize this friend can figure out the complete amperage (It) making use of Ohm"s Law:

I complete (It) = 12V / 8 Ohms = 1.5 Amps

Therefore the complete amperage between the two resistive paths need to equal 1.5 Amps (Rule 3). Now we can number out specifically what each path is pulling utilizing Ohm"s law once more. Remember that the voltage is the same everywhere in a parallel circuit. Therefore we understand the voltage and also the resistance:

I1 = 12V / 12 Ohm = 1 A I2 = 12V / 24 Ohm = .5 A

We figured the complete amperage (It) previously, so currently we can dual check if the figures are correct:

I1 + I2 = the 1A + .5A = 1.5A - check


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"If one of the parallel paths is broken, current will proceed to flow in every the other paths."

The best means to highlight this is additionally with a wire of irradiate bulbs in paralallel. If one is burnt out, the others continue to be lit.