What is Direct Current? – DC

Direct Current (DC), is the result of the flow of electrons (negative charge) in a conductor (most of the time, wires of copper) that goes only in one direction.

What is Electrical Resistance? Obtaining a material’s resistance

The electrical resistance is a measurement of the opposition that offers a material to the passage of electrons (the electric current). When a material, such as metals has many free electrons, it allows the easy flow of electrons and it is called conductor.

What is Electrical Resistivity?

Electrical resistivity [ρ] (rho) is a characteristic of materials and has ohm-meter unit. Resistivity indicates how much the material opposes the flow of electric current.

Mesh analysis in a resistor network – Mesh current method in a resistor network.

Mesh current analysis or the mesh current method is a technique used to find the currents circulating around a mesh with in any closed path of a circuit.

Resistors in series and parallel How to obtain the equivalent resistor value of resistors in series and parallel. Resistors in series To implement a circuit with resistors in series you have to connect one resistor after the other one. (see the image). The equivalent resistor value of the resistors connected in series is equal to the […]

First Right Hand Rule

The First Right Hand Rule or (Magnetic Force induced on a Current-Carrying Wire) says that if a current-carrying wire is in the presence of a magnetic field, a force is exerted on the wire.

Capacitor Discharge Process.

In a series RC circuit, a capacitor does not immediately discharge after being disconnected from a power source of direct current. The capacitor voltage Vc decreases from the initial voltage on the capacitor to 0 volts in some amount of time.

The capacitor charging process

The capacitor charging process shows the variation of voltage and current in the capacitor over time, when it is connected to a DC voltage source

DC Motor

A DC motor is composed of a stator and a rotor. In many small motors, the stator is composed of magnets. Larger motors have windings.

Static Electricity – What it is?

Static electricity is static, since it is a current that is going nowhere. Both, DC and AC current flow in some direction, but estatic electricity does not.

Internal resistance of a voltage source

Voltage sources, whether batteries, generators, etc., are not ideal (perfect). A real voltage source is composed of an ideal voltage source in series with a resistance called internal resistance.

Temperature effects on resistance. Resistance Variation with Temperature.

The value of the resistance of a material varies with temperature change. For this reason, the circuit or system containing these elements should work in controled environment