science

Line regulation

Line regulation is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Line regulation rather than just read about it. In short: Line regulation is the ability of a power supply to maintain a constant output voltage despite changes to the input voltage, with the output current drawn from the power supply remaining constant. Line Regulation = Δ V o Δ V i ⋅ 100 % {\displaystyle {\text{Line Regulation}}={\frac {\Delta V_{\text{o}}}{\Delta V_{\text{i }}}}\cdot 100\%} where ΔVi is the change in input voltage while ΔVo is the corresponding change i…

Key takeaways

Line regulation belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Line regulation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Line regulation from memory before moving on to harder problems.

Reference excerpt

Line regulation is the ability of a power supply to maintain a constant output voltage despite changes to the input voltage, with the output current drawn from the power supply remaining constant.

Line Regulation = Δ V o Δ V i ⋅ 100 % {\displaystyle {\text{Line Regulation}}={\frac {\Delta V_{\text{o}}}{\Delta V_{\text{i }}}}\cdot 100\%}

where ΔVi is the change in input voltage while ΔVo is the corresponding change in output voltage. It is desirable for a power supply to maintain a stable output regardless of changes in the input voltage. The line regulation is important when the input voltage source is unstable or unregulated and this would result in significant variations in the output voltage. The line regulation for an unregulated power supply is usually very high for a majority of operations, but this can be improved by using a voltage regulator. A low line regulation is always preferred. In practice, a well regulated power supply should have a line regulation of at most 0.1%. In the regulator device datasheets the line regulation is expressed as percent change in output with respect to change in input per volt of the output. Mathematically it is expressed as:

Line Regulation = Δ V o Δ V i ⋅ V o ⋅ 100 % / V {\displaystyle {\text{Line Regulation}}={\frac {\Delta V_{\text{o}}}{\Delta V_{\text{i }}\cdot V_{\text{o}}}}\cdot 100\%/V}

The unit here is %/V. For example, In the ABLIC Inc. S1206-series regulator device the typical line regulation is expressed as 0.05%/V which means that the change in the output with respect to change in the input of the regulator device is 0.05%, when the output of the device is set at 1V. Moreover, the line regulation of the device expressed in the datasheet is temperature dependent. Usually the datasheets mention line regulation at 25 °C.

See also Load regulation Linear regulator

Notes

Worked examples

Example 1 — a first encounter with Line regulation

Start with the simplest possible case. Write down what Line regulation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Line regulation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Line regulation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Line regulation

In research: Line regulation appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Line regulation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Line regulation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electric power stubs, Electrical power control, so understanding it makes those chapters shorter.
In everyday life: Look for Line regulation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Line regulation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Line regulation means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Line regulation out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Line regulation in simple terms?

Line regulation is the ability of a power supply to maintain a constant output voltage despite changes to the input voltage, with the output current drawn from the power supply remaining constant. Line Regulation = Δ V o Δ V i ⋅ 100 % {\displaystyle {\text{Line Regulation}}={\frac {\Delta V_{\text{…

Why does Line regulation matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Line regulation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Line regulation.