Image description

The image shows the simplified diagram of any electrical circuit, a connection between several electrical components, attached to an electrical network in a closed loop or a path through which electricity flows, travelling back and forth.

The electrical network illustrated in the image is a linear one, rendered by a blank and horizontal rectangle, outlined with a thin line, at the edges of which are two generators or batteries, marked with plus and minus charges, at the left end, and a lamp or a light bulb. receiver, at the right end.

The electric batteries on the left side of the circuit are rendered by the specific symbol, respectively, two parallel lines, spaced between them, the longer line being up and the shorter down, denoted by the plus and minus charges.

The light bulb on the right side of the circuit is illustrated by the specific symbol, respectively a small blank circle, crossed on its center by an x.

The circuit in the image is a complex one, with four loops, counting from left to right, marked by four blank and vertical rectangles that form the main large, horizontal rectangle.

A loop must have at least two sides and be a closed shape, as shown in the figure, a rectangle through which the line passes once through each node.

The resistor on the right side of the second loop, center, is a component of the electrical circuit with the role of reducing the current voltage between two points and is highlighted by a blank and vertical rectangle.

Like the resistor, the capacitor is a simple passive device that is used to “store electricity” on its boards. A capacitor is a component that has the ability to store energy in the form of an electrical charge that produces a potential difference or static voltage on its boards, just like a small rechargeable battery. (5)

The capacitor located to the right side of the first loop, center, is highlighted by two horizontal lines, short and parallel.

The voltmeter to the right of the third loop is marked by a blank circle, in the center of which the letter V is noted.

The voltmeter is used to measure the voltage of the electric current in volts.

At the top of the electrical circuit, on the first eye is mounted an inductor, also called a coil, represented by the specific symbol, respectively a wavy line, with three loops.

The inductor is a coil with rolled copper armature, which stores energy in a magnetic field when electric current flows through it.

Also at the top of the circuit, on the second loop, there is an ammeter, shown by a blank circle, in the center of which the letter A is inscribed.

The ammeter is used to measure the intensity of electric current in amperes.

General information

The electric circuit is the path the electrical current has to travel between a power source and an electrical powered device. The circulation or travelling of electrical current between the source and the consumer is achieved using electric conductors, such as the connecting wires. Therefore, the mandatory main components of an electric circuit are:

  • one or more energy sources;
  • one or more consumers;
  • connecting wires through which the electrical current flows.

Other secondary components, meaning not compulsory, may be:

  • an electrical condenser or capacitor;
  • a coil (electrical inductor);
  • a resistor;
  • a diode.

Each circuit component has an international symbol. For example, the coil is represented through the letter “L”, the capacitor is marked as “C”, the resistor is “R”, the battery is “U”.

The present image attached to this text reproduces an electric circuit comprised of two batteries which represent the energy sources, a coil, a capacitor, an ammeter, a voltmeter, a resistor and an incandescent light bulb, which is the consumer. 

A coil or electrical inductor is a copper wire wrapped around an iron core. This simple device has many usages, out of which we should name the electrical generators and the engines or motors. A very important fact to keep in mind is that the flow of electric current through a coil generates a magnetic field. Within the present mentioned circuit, the coil is just an element through which the electric current passes, without any practical functions.

The capacitor or electric condenser is an electric device that stores energy, similarly to a tiny battery with a very small capacity. It is made out of two electric conductors, divided by a non-conducting area. We can say that a capacitor is a small energy reservoir that can be used to stabilize the current, in case the main power source is unavailable for a short amount of time. Speaking of our circuit, if we are to disconnect the batteries for a very short time, the incandescent light bulb will not be turned off because it would continue to receive power from the current already stored inside the capacitor.

The resistor is a device that reduces the current intensity inside an electric circuit. Practically, the resistor tones down the intensity of the electric current, just like a thin hose slows down the water flowing through it. In the case of our circuit, in order to reduce the amount of current that enters the incandescent electric bulb a resistor had to be connected.

The ammeter is a device that measures the intensity of the current. We can measure the current intensity at the terminals or ends of the two batteries from our circuit, or we can measure the intensity of the current that flows through the circuit’s resistor.

The voltmeter is a device that measures the electrical voltage. We can measure the voltage at the terminals or ends of each battery from our circuit, in order to check the charging level, or we can measure the voltage drop at the ends of the batteries, which resulted after connecting the incandescent light bulb to the two batteries.

Did you know that there are multi-meters, meaning certain modern devices which are able to measure multiple things? With the help of a single device we can thus measure the voltage, the current intensity, as well as the electrical resistance of a material.


  1. https://ro.wikipedia.org/wiki/Bobin%C4%83
  2. https://hobbytronica.ro/capacitatea-inductanta-si-rezistenta-electrica/
  3. https://ro.wikipedia.org/wiki/Ampermetru
  4. https://sites.google.com/site/electricitatesienergie/curentul-electric

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