Electric Circuits

Your Home Solutions works on closed connections of batteries, resistors, and wires. The push of electric charge from one end of a battery to the other is the power that runs an electric circuit.

You will need a battery, two insulated wires, and a light bulb to build a simple circuit. To start, you must strip the ends of each insulated wire with wire strippers to expose them completely.


Voltage is the energy, or potential difference, between points in an electric circuit. It acts as the “pressure” that motivates the flow of electric charges (electrons) through a conducting loop, enabling them to do work such as illuminating a light bulb. Voltage is usually measured in volts, a name that honors Italian physicist Alessandro Volta, who invented the voltaic pile–the forerunner of today’s household batteries.

Two points connected by an ideal conductor with no changing magnetic field have zero voltage. As the magnetic field changes, the voltage of those points also changes. The closer the distance between the two points, the larger the voltage.

In an electrical circuit, a voltage source such as a battery or wall outlet provides the electricity needed to push electric current through the wires that connect those two points. An electrical circuit is complete when a device at the end of the wires can use the electricity. In the simplest cases, this device may be as simple as a light-emitting diode or lamp that lights up when current passes through it.

The voltage in an electric circuit is measured by placing the measuring device in parallel with the component or circuit to be tested. This allows the voltage to be measured without disturbing the circuit. The measuring device must have an infinite input impedance, meaning it will not absorb any energy from the tested circuit.

When a component in an electric circuit is connected in series, its voltage adds up across all of the components in the circuit. For example, in a battery-powered circuit with four LEDs connected in series via a resistor, each LED will receive 4V from the battery. The total current through the circuit is 2A because of 4V (1A / resistor). The resistance of the entire circuit is 10. If the battery voltage is doubled, the current will also double. Similarly, if the resistance of the circuit is tripled, then the current will triple as well.

The current in an electric circuit is the flow of charged particles called electrons. Electrons travel along a circuit’s wires and deliver energy to the electrical load connected to the circuit. The current can be direct or alternating, either a constant value (ac) or reverses direction at regular intervals (dc). The current in a given circuit is measured in amperes or amps. One ampere is the number of coulombs of charge that pass a point on the circuit in 1 second.

It can be helpful to think of an electric circuit’s current as like water flowing downhill. Once the water reaches the bottom of the hill, it must be lifted back up to the top by some other means. This is what a battery or power source does in an electric circuit.

In a simple electric circuit, the current flow is initiated by an electricity source and carried by conducting wires to a light bulb or other energy device. The electric field signal from the source travels at nearly the speed of light to all mobile charge carriers in the circuit, including the electrons in the copper atoms in the wires, and orders them to start marching. As they move through the circuit, the electrons must continuously collide with fixed atoms to keep moving in the same direction, and the circuit’s voltage regulates their movement.

There is no place in an electric circuit where the current stops or stalls, even if there are multiple breakages in the conducting material. This is because the flow of electrons depends on an unbroken loop of conductive material. If any part of the circuit breaks down, it will not be possible for electrons to move continuously from one end of the circuit to the other.

A circuit’s resistance is its opposition to electric current flow. It is measured in units called ohms (resistance, R; current, I). Resistance limits how much electricity can travel around a circuit. It is often used with other electrical components to control how much current flows through them.

The more resistance a circuit has, the lower the current. This is because moving electrons across the circuit consumes a certain amount of energy. Several factors determine the amount of resistance. For example, the material that a conductor is made of determines its resistance to some degree. Metals are better conductors than plastic or rubber, but they still have some resistance. The length and cross-section area of the conductor also determines its resistance, as does its operating temperature.

All materials have some resistance to electric current flow, which is why the formula for calculating the overall resistance of a wire or conductor is quite simple: R = 1/(len(the conductor) * 2/(uniform cross-sectional area of the conductor) + outside factors). This formula can be simplified for smaller wires or shorter conductors by dividing the total resistor value by 2.

Resistance can be very varied. Some metals, such as silver, are very good conductors and offer little resistance to the flow of electrons. Other metals, such as copper and aluminum, are less costly but have relatively low resistance. In contrast, some materials, such as rubber, paper, and glass, offer high resistance to the flow of electrons.

Electricity flowing through a wire not designed to be a good conductor will make it hot, which can damage or shorten the wire. It is, therefore, sometimes useful to add electrical resistance into a circuit to prevent overvoltage and overcurrent, which can cause electronic equipment to overheat and fire. Resistance can be changed by using different types of metals or even adding or removing wires from the circuit. The resistance of a resistor is generally measured with an instrument such as a digital multimeter, which uses a two-wire method to detect a current.

An electric circuit is a closed path that allows current to flow. It consists of devices that give out energy to electrons, such as batteries, bulbs, and wires connecting the components. There are two main types of circuits: series and parallel. The performance of an electric circuit is governed by Ohm’s law and Kirchhoff’s laws.

The power in an electric circuit is determined by the amount of current and voltage it uses up, as well as how fast that happens. Some circuits disperse power very quickly, while others disperse it more slowly. Electricity is measured in watts, the amount of power used up in a second.

There are three ways that power is expressed: instantaneous power (P_textiPi), average power (P_textaPa), and peak power (P_textppkPpk). Each is determined by how much energy a circuit consumes at different times. Instantaneous power measures how much energy is consumed at one time. In contrast, average and peak power measures how much power is consumed over an extended period.

Every electric circuit needs a source of electricity, usually a battery or a wall outlet. The source generates electricity by converting chemical energy into electric potential energy and then electric current. Electrons can then flow through the circuit and transform that potential energy into other forms of energy, such as thermal, light, sound, or mechanical.

A simple circuit consists of a battery, a bulb, and wires connected to both the positive and negative ends of the battery. If the power source is switched on, the bulb will illuminate. If the switch is switched off, the bulb will go out. This is an example of a parallel circuit.

In a parallel circuit, all electrical components are connected across multiple paths. Each device has its resistance, so the overall circuit resistance is the sum of all the individual resistances. The power in a parallel circuit is equal to the voltage and current product. This is why a parallel circuit is so safe to use with household appliances. If there is a failure in one part of the circuit, it does not affect the rest of the circuit.