Devices for Measuring Electric Current
The operation of electric current measuring devices is based on the voltage differential resulting from the flow of current in an electric circuit. By connecting the circuit in series with a resistor, we can measure the voltage difference, which allows us to calculate the electric current.
One of the most notable instruments for measuring electric current is the ammeter, which is capable of measuring current intensity regardless of its level. Various types of ammeters exist, each differing in measurement accuracy and operating principle. Below are the main types:
- D’Arsonval Ammeter
The D’Arsonval ammeter measures direct current intensity with an accuracy ranging from 0.1% to 2%.
- Electrodynamic Ammeter
The electrodynamic ammeter is designed to measure both alternating and direct current intensities, with an accuracy range between 0.1% and 0.25%.
- Thermal Ammeter
The thermal ammeter is used to measure alternating current intensity, offering an accuracy range of 0.5% to 3%.
- Digital Ammeters
Digital ammeters are utilized for measuring direct current intensity with precision exceeding 0.1%.
Devices for Measuring Electric Voltage
The principle behind electric voltage measuring devices involves measuring the voltage difference between two points by connecting the voltmeter in parallel with the power source.
Voltage measuring devices vary based on calibration accuracy and measurement scale, typically displaying results in volts, millivolts, or kilovolts. Here are the key types of voltage measuring devices:
- Digital Voltmeter
Digital voltmeters measure voltage differences with greater accuracy than analog voltmeters, providing direct readings on a digital display.
- Analog Voltmeter
The analog voltmeter operates by reading the current flowing through the wires and converting it to a voltage reading through a mechanical process.
- Electrostatic Voltmeter
The electrostatic voltmeter measures electrical voltage by generating electrostatic forces, obtaining direct readings without needing to measure current intensity, distinguishing it from other voltage measuring devices.
- Potentiometer
The potentiometer measures very low electrical voltage that may be difficult to read with other devices.
- Electronic Voltmeter
The electronic voltmeter measures electrical voltage without the possibility of error in the electric circuit, relying on amplification or correction as necessary to provide readings for both direct and alternating voltages.
Devices for Measuring Electric Resistance
The principle of electrical resistance measuring devices involves supplying a known voltage to the circuit via a resistor and measuring the resulting current intensity, enabling the calculation of electrical resistance.
The ohmmeter can be employed to measure resistance in an electric circuit. When the resistance is connected to the device, it can be configured in series or parallel, affecting how resistance changes as current varies. Resistance is measured in ohms.
Devices for Measuring Electric Capacitance
Capacitance measuring devices function by supplying a known voltage to the electrical circuit and measuring the resultant electric charge to determine the capacitance.
Capacitance can be measured using a capacitor meter, which operates on the principle of constant voltage and stored energy until a certain amount of charge is generated. The unit of capacitance measurement is the farad.
Devices for Measuring Electric Inductance
The working principle of inductance measuring devices involves supplying a known amount of current to an electrical circuit and measuring the resulting voltage differential to ascertain the inducement generated in coils and transformers, which is influenced by the magnetic field. Inductors are used in the circuit to measure inductance, denoted by the symbol L, and measured in henries.
Devices for Measuring Frequency
The operation of devices measuring electrical frequency is based on counting the number of occurrences of a specific electrical wavelength within a defined time period.
Frequency can be measured using a frequency meter, which may utilize deviation-based methods to accurately measure frequencies up to 900 hertz.