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

Energy and Electric power.

Power is the speed at which work is done.

Electric power is the multiplication of the current (amps) by the voltage (volts). P = I x V.

What is a Resistor?

A Resistor is an electrical element that causes opposition to the flow of the electric current.  Using the Ohm’s Law V = IxR we can find the voltage on the resistors terminals.

Definition of inductance

An inductor has the property to oppose any change in the current passing through it.

This property is called inductance. When a current flows through a conductor, a magnetic field is created.

Ohm’s Law relates in one equation the voltage, the current and resistance. Resistance = Resistor’s value.

A more complete expression of Ohm’s Law is achieved using the electric power formula

What is a wirewound resistor?

A Wirewound resistor is a resistor made with a conductive wire of a high resistivity. This wire is made of a special alloy and it is wound on a support tube of refractory material such as ceramics, porcelain, etc.

Types of cells / batteries.

– Primary batteries (non-rechargeable): Dry, mercury, alkaline.
– Secondary batteries (rechargeable): Nickel-Cadmium Alkaline, Lead

Cells or Batteries interconnection