Fundamentals of Electrical Measurement and Generation

Electrical Measurement Devices

A multimeter (often referred to as a "tester") is a versatile device used to measure various electrical quantities, including voltage (both AC and DC), current, and resistance.

Circuit Measurement Techniques

• Measuring Voltage

  To measure voltage, the multimeter is connected in parallel across the two points where you want to determine the potential difference.

• Measuring Current

  To measure current (intensity), the multimeter is connected in series, inserted directly into the circuit path where you want to know the current flow.

Understanding Polarity

When taking measurements in a live circuit, the device's pointer might move in the opposite direction or indicate negative values. This occurs if the multimeter's positive (+) and negative (-) terminals are connected in reverse relative to the current's flow direction. To obtain an accurate measurement, simply reverse the connections. Using a crossover switch allows for polarity reversal without physically swapping the leads. Reversing polarity also causes electric motors to change their direction of rotation.

Electrical Current & Generators

Electric current is defined as the flow of electrons along a conductor, driven by the potential difference created by a power generator.

Power generators are devices designed to create electrical current by maintaining a potential difference between the ends of a conductor.

Chemical Process Generators

Chemical process generators consist of two elements called electrodes and a substance called an electrolyte. The electrolyte facilitates a chemical reaction that maintains the potential difference between the electrodes.

Batteries Explained

Batteries are continuous current generators that are non-rechargeable, meaning their internal components degrade and are exhausted over time.

Electromagnetism & Generators

The area of influence surrounding a magnet is known as a magnetic field.

Electromagnetic generators are devices that produce electric current through electromagnetic induction. This induced current is created when a conductor moves between the poles of a magnet, or when a magnet moves inside a coiled conductor (also known as a coil). The rotating element in such a generator is called the rotor, and the fixed component is the stator.