When installing a series circuit, you may notice that devices’ efficiency is affected by increasing the number of connected devices. Meanwhile, if you are connecting them in a parallel circuit, they are not affected, *so why is voltage constant in a parallel circuit but not in series?*

## Why Is Voltage Constant in Parallel Circuit but Not in Series?

**Because in the parallel circuit, there are only two common electrically points, and the voltage, when measured between two common points, will be the same at any time**. Therefore, if you have a circuit with three resistors named R1, R2, and R3. Suppose you measured the voltage difference across any resistor of them, it will be the same.

**In other words, for any resistor you connect, you will use wires to connect them**. Assuming these wires have the same resistance or zero resistance, therefore, the voltage at each end of the wires will be the same because they are connected directly with the source. **Meanwhile, in the series circuits, it’s a different case**.

**The resistors in the series circuit are connected to make the current create a new potential difference as it passes to a new resistor**. So, the voltage of the source is shared between all the resistors. Suppose you want to measure the total voltage of a series circuit. It will be the sum of all voltage drops across each resistor.

## What Does Parallel Circuit Mean?

**A parallel circuit means a connection between two branches. When it moves through the point of connection, the current splits, then, after leaving both branches, the current rejoins again**. The electric circuits or connections have two types series and parallel circuits.

**The voltage is always the same across any two points in the parallel circuits because when connecting any resistor in a parallel circuit, you will use wires. You are then connecting the resistor to the circuit as a branch,** therefore, this directly connects the resistor to the battery’s or source’s negative and positive terminals.

Suppose that you have a circuit consisting of three resistors named R_{x}, R_{y}, and R_{z}, and all the resistors are connected in a parallel connection. In addition, with a battery or a power source, there will be a voltage and a current passing through. The total current “**I**” will be divided between the resistors giving I_{x}, I_{y}, and I_{z}.

So you can calculate any value you want in the circuit by substituting in this equation **V=IR**. For example:

### How To Calculate Voltage in Parallel Circuit?

Suppose we have thee resistors with these values 180 ohms, 90 ohms, and 45 ohms, and the current passing through the circuit is 3.5 amperes. **The first step to calculating the voltage is to know the resistance of the circuit**. The total or the equivalent resistance can be calculated using this equation:

Then you can use the resistance we just calculated and substitute in this equation **V=IR**= 25.7 x 3.5 = 90 volts. Since we know that the voltage is the same across any point in the circuit. We can calculate the current passing through each branch:

### What Is the Advantage of Constant Voltage in Parallel?

**The same voltage across the parallel circuit gives them a big advantage over the series one**. For example, parallel circuits are used in light systems because the lights bulbs will have the same brightness, it doesn’t matter how many connected bulbs; the bulbs will have the same brightness.

**On the contrary, the series circuits don’t have the same feature**. The brightness of the bulbs will be affected by the number of the bulbs connected. The brightness will continue to decrease as you connect more bulbs to the circuit. This is why parallel circuits are used in every household or light system.

### Is Constant Voltage Term in Parallel Circuits Right?

**No, the constant term can’t be used when describing the voltage across the parallel circuit **because the term specifies that the voltage is a fixed value in every circuit. It differs from one power source to another, but it’s the same across the resistors for the same power supply.

For example, if you have three trees in a park, the trees can have the same height but for the ground level but this doesn’t mean that the height value is constant.

### What Are The Uses of Parallel Circuits?

**One of the main features of parallel circuits is that they function independently**. The parallel circuits don’t affect the entire circuitry; therefore, you can see them used in many applications. For example:

**Home Wiring System**

**The wiring in any household is done using parallel connections and circuits**, this allows the appliances and devices to operate without getting affected by others. So, if one device fails, the others continue to work as if nothing happened.

Imagine having a light bulb connected in series. If it turned off or got burnt, then all the other connected applications will have no power.**Cell Phones**

**Parallel circuits are widely used in cell phones circuits. Their circuits use IC power to supply memory, processor**, sensors, display, and many other components.

**Related Readings:**

**Why Do Parallel Resistors Have Less Resistance?**

**What Happens if You Switch Neutral And Ground Wires?**

**What Color Wires Can Go Together? Complete Guide**

**Why Voltage Decreases When Current Increases?**

**How To Identify Wires On A Thermostat? (How To DIY)**

**Why Does a Potentiometer Have 2, 3 & 6 Legs?…**

## What Does Series Circuit Mean?

**Series circuits have resistors such as a light bulb and have a power source such as a battery. The series circuit is connected directly to the power source without the presence of any branches**. Any component in the circuit is connected from one end to the bulb and the other end to the battery.

**If there are any disconnections or gaps, they will cause the applications to fail, and there will be no power**. Series circuits have two types natural and artificial circuits. Artificial circuits need a breaker or fuse to be installed to prevent any power surge or hazards. **The current passing through the circuit is constant**.

**Because there are no branches in the circuit so the current entering the first resistor is the same as entering the second resistor**. This means the voltage will not be the same across the resistors of different resistances.

### How To Calculate Voltage in Series Circuit?

Suppose we have thee resistors with these values 25 ohms, 50 ohms, and 75 ohms, and the current passing through the circuit is 3.5 amperes. **The first step to calculating the voltage is to know the resistance of the circuit.** The total or the equivalent resistance can be calculated using this equation:

Then you can use the resistance we just calculated and substitute in this equation **V=IR** = 150x 3.5 = 525 volts. Since we know that the current is the same through any point in the circuit. We can calculate the voltage across each resistor:

### What Are The Uses of Series Circuits?

**Although series circuits have different voltage across resistors, they are used in many applications**. Since they are easy to learn and handle, electronic designers can customize and apply changes to perform certain functions. For example:

**Voltage Dividers**

**Not all devices have the same voltage levels; you need to divide the voltage to power them**. Therefore, resistors are connected in series to divide the voltage. For example, taps need certain voltage levels to operate, so other components are connected with them.**Battery Voltage**

**Since voltage increases of batteries increase when in series connection; small batteries are used to create a larger battery**. For example, if you have two 2-volt batteries connected together. They will create a 4-volt battery, however, you need to consider the battery’s ampere-hour capacity.

## Conclusion

To sum up, **parallel circuits have the same voltage across their components, meanwhile, the series circuits don’t. In the parallel circuits, the components are connected directly to the power source’s terminal** (positive and negative), but in the series, the components have one end connected to the power source and the other to the rest of the devices.

**The parallel circuits have more advantages over the series ones, this makes them widely used in many applications and systems,** such as home wiring, however, series circuits are also used in certain applications.

I’m ambitious and peaceful, always seeking to improve and learn more. I love reading and writing; writing helps me think better and clear my mind. One of my hobbies is DIY projects; I love doing everything myself. It feels so good to teach other people what you know; helping people makes a great person out of you.