Electric current refers to the flow of electric charge in a conductor. It is measured in units called amperes (A) and denoted by the symbol "I." Electric current can be either direct current (DC), where the flow of charge is in one direction, or alternating current (AC), where the flow of charge periodically reverses direction.
Ohm's law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points, while the resistance of the conductor remains constant. Mathematically, Ohm's law expressed as:
V = I * R
- V represents the voltage across the conductor,
- I represents the current flowing through the conductor, and
- R represents the resistance of the conductor.
This relationship allows us to calculate any one of the three variables (voltage, current, or resistance) if we know the values of the other two.
Electrical Measuring Devices:
1. Galometer: A galvanometer is an instrument used to detect and measure small electric currents. It works based on the principle of electromagnetic induction. Galvanometers are often used as the basis for more advanced measuring devices like ammeters and voltmeters.
2. Ammeter: An ammeter is a device used to measure the electric current in a circuit. It is connected in series with the circuit, allowing the current to pass through it. Ammeters have low resistance to minimize their impact on the circuit's current flow.
3. Voltmeter: A voltmeter is an instrument used to measure the voltage difference between two points in an electrical circuit. It is connected in parallel with the component or circuit being measured, allowing it to measure the potential difference across that component. Voltmeters have high resistance to prevent significant current flow through them.
4. Ohmmeter: An ohmmeter is a device used to measure the resistance of a component or circuit. It applies a known voltage to the component and measures the resulting current flow. Based on Ohm's law, the resistance can be calculated by dividing the applied voltage by the measured current.
These measuring devices are essential tools in electrical engineering and help in analyzing and troubleshooting electrical circuits.
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