Standard Element Values
Standard Element Values - Related Videos
02:37
Standard Enthalpy of Formation
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2020
Enthalpy changes are typically tabulated for reactions in which both the reactants and products are at the same conditions. A standard state is a commonly accepted set of conditions used as a reference point for the determination of properties under other different conditions. For chemists, the IUPAC standard state refers to materials under a pressure of 1 bar and solutions at 1 M and does not specify a temperature. Many thermochemical tables list values with a standard state of 1 atm. Because...
04:00
Periodic Classification of the Elements
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2020
The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their electron configurations are added to the table, a periodic recurrence of similar electron configurations in the outer shells of these elements is observed. Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. The outer electrons have the highest energy of the electrons in an atom...
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Professional Values
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2023
Nurses are responsible for caring for patients during birth, death, illness, and healing. Professional values guide the decisions and actions that nurses make in their careers. If nurses know the decisions and actions to take, providing patients with exceptional care is possible. The values that are the foundation of the nursing profession are altruism, autonomy, human dignity, and social justice. First, altruism refers to the concern for the welfare and well-being of others without personal...
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Critical Values
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2025
A critical value is a definite value obtained from a particular probability distribution at a predecided confidence level (or a predecided significance level) for a given population parameter. The critical value provides demarcation that separates the sample statistics that are likely to occur from the ones that are unlikely to occur based on the given probability distribution and the population parameter to be estimated. The critical value for normal distribution is obtained from the z...
02:31
Elements: Chemical Symbols and Isotopes
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2020
A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is used to indicate one atom of mercury (microscopic domain) or to label a container of many atoms of the element mercury (macroscopic domain). Some symbols are derived from the common English name of the element; others are abbreviations of the name in another language — Latin, Greek or German. For example, the symbol for aluminum (common name)...
FAQs
A logarithmic progression spaces nominal values by decade rather than by equal arithmetic increments. This lets a selected sequence cover changing magnitudes while remaining compatible with the way component tolerances define acceptable variation around a nominal value. In engineering design, that arrangement reduces the need to catalog every numerical possibility and makes value selection consistent across component ranges.
E6, E12, and E24 provide different densities of nominal choices within each decade. The selected series therefore affects how closely a designer can match a calculated requirement and which typical tolerance is associated with the available values. Comparing these series helps engineers balance finer value selection against practical catalog and manufacturing considerations during design.
A nominal value is the specified target, not a claim that every manufactured part has exactly that number. The component’s tolerance describes the expected allowable variation around that target. Treating those together prevents engineers from selecting a nominal value in isolation and supports more realistic estimates of circuit behavior when documenting or evaluating a design.
Start with the value required by the circuit, then identify a nearby nominal value in an appropriate E-series. Check the associated typical tolerance and confirm that the part can be obtained from the intended catalog or procurement source. Finally, use the selected nominal value and tolerance when estimating circuit behavior and recording the design.
A closer nominal match is not automatically the best engineering choice. Designers should weigh the required circuit performance against whether the component is available, affordable, and consistent with manufacturing needs. Selecting a practical series and value can simplify procurement and production, even when several nominal options could approximate the calculated requirement.
In resistor and capacitor catalogs, the organized series gives engineers a consistent vocabulary for specifying parts and recording design choices. Documentation can identify the selected nominal value, its series context, and its typical tolerance while circuit estimates use the same information. This improves continuity between design calculations, component selection, procurement, and manufacturing.