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What is electrical resistance?
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Electric resistivity is defined as the electrical resistance offered per unit length and unit cross-sectional area at a specific temperature and is denoted by ρ. Electrical resistance is also known as specific electrical resistance.
- 3 min
- What Is Electrical Resistance?
- Types of Materials and Their Resistance
- Measuring Resistance
- Fixed-Resistance Components
- Practical Applications of Resistance
- Measuring Resistance in Circuits
- Examples of Circuit Resistance
- Troubleshooting with Resistance Measurements
- About Electrical Resistance
Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). Ohms are named after Georg Simon Ohm (1784-1854), a German physicist who studied the relationship between voltage, current and resistance. He is credited for formulating Ohm's Law.
All materials resist current flow to some degree. However, when it comes to resistance, most materials fall into one of two broad categories: 1. Conductors:Materials that offer very little resistance allow electrons to move easily. Examples: silver, copper, gold, and aluminum. 2. Insulators:Materials that have high resistance restrict the flow of e...
Before measuring resistance, it’s important to know how your measurement tool displays results. Resistance measurement results look very different depending on if you’re measuring in ohms (Ω), kiloohms (kΩ), or another unit. Also, to ensure you get an accurate reading, make sure the component you’re testing is powered down or disconnected from the ...
Many components, such as heating elements and resistors, have a fixed-resistance value. These values are often printed on the components' nameplates or in manuals. When a tolerance is indicated, the measured resistance value should be within the specified resistance range. Any significant change in a fixed-resistance value usually indicates a probl...
"Resistance" may sound negative, but when it comes to electrical systems, it can be used beneficially. For example, thanks to high resistance, current struggles to flow through the small coils of a toaster, generating enough heat to toast bread. Old-style incandescent light bulbs also force current to flow through thin, high-resistant filaments, wh...
Resistance cannot be measured in an operating circuit. Accordingly, troubleshooting technicians often determine resistance by taking voltage and current measurements and applying Ohm's Law: E = I x R This means that the voltage (E) across a circuit is equal to the current (I) flowing through it times the resistance (R). That is, volts = amps x ohms...
Normal Circuit Resistance
In an electric heater circuit, as portrayed in the two illustrations below, resistance is determined by measuring circuit voltage and current, then applying Ohm's Law. In the first example, total normal circuit resistance, a known reference value, is 60 Ω (240 ÷ 4 = 60 Ω). The 60 Ω resistance can help determine the condition of a circuit.
Increased Circuit Resistance
In the second example, if circuit current is 3 amps instead of 4, circuit resistance has increased from 60 Ω to 80 Ω (240 ÷ 3 = 80 Ω). The 20 Ω gain in total resistance could be caused by a loose or dirty connection or an open-coil section. Open-coil sections increase the total circuit resistance, which decreases current.
Knowing the electrical resistance in a circuit or component can be useful when troubleshooting electrical problems. Measuring resistance is a straightforward way to identify whether components are operating properly. By measuring resistance at different points in a circuit, you can pinpoint where the failure is and more quickly restore the circuit ...
Electrical resistance is an important property of electricity that controls the flow of current in electrical systems. It can also be a key indicator of installation errors, poor connections, and failed components. While resistance can be determined using Ohm’s Law, it can also be measured with specialized tools like a multimeter or ohmmeter. Under...
Jul 11, 2021 · Resistance (also known as ohmic resistance or electrical resistance) is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). The larger resistance, the greater the barrier against the flow of current.
Aug 8, 2024 · Resistance, in electricity, property of an electric circuit or part of a circuit that transforms electric energy into heat energy in opposing electric current. Resistance involves collisions of the current-carrying charged particles with fixed particles that make up the structure of the conductors.
- The Editors of Encyclopaedia Britannica
Resistance ® is a measure of how difficult it is for current to flow. Resistance is measured in units called ohms (Ω). The amount of. current. flowing in a circuit is...
The resistivity is a characteristic of the material used to fabricate a wire or other electrical component, whereas the resistance is a characteristic of the wire or component. To calculate the resistance, consider a section of conducting wire with cross-sectional area A, length L, and resistivity .
Dec 28, 2020 · Definition of Resistance. Electrical resistance is a measure of opposition to the flow of electric current.
