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.

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.

Types of cells / batteries.

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

Cells or Batteries interconnection

Step Response of RL Circuits When a constant voltage is suddenly applied to an RL circuit, an increasing a current goes through the conductor and creates a magnetic field that expands with the increasing current. This current will reach a maximum value, and the magnetic field stop expanding. The expanding magnetic field induces a Counter-Electromotive Force […]

Inductor in DC and AC.

Phase angle of the alternating current in an Inductor,

The quality factor (Q)

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.

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 has two parts

– A transient part where values of Ic and Vc varies with time. (Approximately 5 times the time constant T).
– A stable part where values of Vc and IC are constant.

Capacitor and Direct Current.

Direct Current that varies over time, the current starts from a maximum value and decreases to 0 amperes, when there is no current flow. This happens in a very short period of time and is called “transient current”.

Series and Parallel Resistor Reduction.

Simplifing a series resistor circuit and / or parallel resistor circuit is simple, it is only necessary to make the necessary simplifications using formulas we already know

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

Benjamin Franklin’s Fluid Theory

Benjamin Franklin imagined the electricity as a invisible fluid.

Franklin assured that if any body had more fluid than usual, it could have a positive charge, but if it had less fluid than normal it had negative charge.