Resistance quantization circuit exerts resistance to the flow of current – Delixi

We are able to compare the values of resistance and hose diameter (conductance vs. practical diameter). When it comes to metal wires, this analogy works well. Small-diameter wires have a higher resistance than large-diameter wires made of the same metal.

The standard unit of resistance is the ohm, sometimes indicated as the capital Greece letter Omega (Q). You will also hear about kilowatts (indicated as k or kQ) where 1 k = 1000 ohms, or about megaohms (indicated as M or MQ) where 1 M = 1,000,000 ohms = 1000 k. In this book, we will never use the omega symbol. Instead, we'll always write "ohm" or "ohms" in its entirety.

Resistance quantization circuit exerts resistance to the flow of current – Delixi

Resistance quantization circuit exerts resistance to the flow of current – Delixi

Sometimes the resistivity of a wire is evaluated. The standard units used for this intent are ohms per foot (ohm/ft) or ohms per meter (ohm/rn). You may also encounter units of ohms per kilometer (ohm/km). Table 2-1 shows the resistivity values of solid copper wire at room temperature at various general scales, which is a function of wire diameter defined by a scheme called "United States Wire Gauge (AWG)."

When we apply a potential difference of 1V to a module with a resistance equal to 1 ohm, the current is 1A, assuming that the power supply can supply an infinite number of charge carriers. If the resistance is doubled to 2 ohms, the current will be reduced to 0.5A. If you reduce the resistance by a factor of 5 to only 0.2 ohms, the current will increase from 1 A to 5 A by the same multiple. The current with respect to the stable voltage, which changes inversely in proportion to the resistance, shows the current through the various resistive components with a stable potential difference of 1 V.

Circuits always have a definite resistance. There is no such thing as an ideal conductor (an object with mathematically zero resistance) in the real world. When scientists cool certain metals to temperatures close to affirmative zero, these substances lose almost all of their resistance, so that current can flow for long periods of time. This phenomenon is called superconductivity. However, nothing can be a perfect conductor. Such an object would in practice constitute a perpetual motion machine.

Just as there may not be a substance in the real world that is completely free of resistance, we will never encounter an infinite amount of resistance. Even dry air conducts electricity to some extent, although the effect is generally small enough for scientists and engineers to ignore. In some electronic uses, engineers choose materials based on the "almost infinite" occurrence of resistance. But when they say that, they use analogies. What they really mean is that the revolt is so great that we can see it as "infinite" for all practical uses.

In electronic devices, the resistance of a component generally varies depending on the conditions under which the component operates. For example, transistors may sometimes have high resistance and sometimes low resistance. High/low resistance changes can occur thousands, millions, or billions of times per second. In this way, oscillators, amplifiers, and digital devices work in radio receivers and transmitters, telephone networks, digital computers, and satellite links, to name a few.

Resistance quantization circuit exerts resistance to the flow of current – Delixi

Sections viewed

Contact

working hours