Electrical circuits

Basic electrical circuit. The voltage source on the left side drives the electrical current around the circuit, conducting electrical energy into the resistance. The current returns from the resistor to the source and completes the circuit.

An electrical circuit is an interconnection of electrical components, usually intended to perform some useful function with a return path to enable the charge to return to its source. The components of an electrical circuit take many forms, and these forms may include elements

Such as resistors (resistor), capacitors (capacitor), switches (switch), transformers (transformer), and electronics. Electronic circuits include active components (active component), which are usually semiconductors and appear non-linear, requiring complex analysis. The simplest electrical components are those described as passive and linear. While these components store energy temporarily, they do not contain energy sources. They also produce linear responses to stimuli.

A resistor is probably the simplest passive element in an electrical circuit. As its name suggests, it resists the electrical current passing through it and dissipates its thermal energy. Resistance is the result of the movement of electrical charge through a conductor. For example, resistance in metals is mainly due to the collision of electrons with ions. Ohm’s law is considered the basic law of electric circuit theory. This law states that the current passing through a resistance in a conductor is directly proportional to the potential difference between its ends. The resistance of most materials is relatively constant over different temperatures and electrical currents. Substances that meet these conditions are described as “ohmic”. The name Ohm, which is the unit of measurement of resistance, was named after its creator, Georg Ohm, and is symbolized by the Greek letter “Ω”. The symbol “1 Ω” indicates the resistance that will produce a potential difference of one volt in response to a current of one ampere.

The capacitor is a device that stores electrical charge, and thus stores electrical energy in the field resulting from this process. Conceptually, a capacitor consists of two conductive plates separated by a thin insulating layer. In practice, thin metal foils are rolled together which increases the thickness of the surface area in terms of unit volume and capacitance. The unit of capacitance is the farad, named after Michael Faraday and symbolized by the symbol “F”. One farad equals the capacitance that arises from a potential difference of one volt when it stores a charge equal to one coulomb. A capacitor connected to a voltage supply initially causes an electric current to flow; As it collects electrical charge. However, the electric current decays over time as the electrolytic capacitor fills and gradually reaches zero. Therefore, the capacitor does not allow current to flow in steady state, but rather blocks it.

In addition, an inductor is a conductor, usually a coil of wire, that stores energy in the magnetic field in response to current passing through it. When the current changes, the magnetic field changes accordingly and induces an electric voltage between the two ends of the conductor. The induced voltage is proportional to the time rate of change in the electric current. The constant of proportionality is called inductance. The unit of inductance is a “Henry,” after Faraday’s contemporary, Joseph Henry. One Henry equals the inductance that induces a potential difference of one volt if the current passing through it changes at a rate of one ampere per second.

 The way the induction coil works is sometimes reflected in the way the capacitor works, meaning that it allows an unchanging current to pass easily, but it resists the passage of a rapidly changing current.