science

Wiegand sensor

Wiegand sensor 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 Wiegand sensor rather than just read about it. In short: Wiegand sensors are magnetic sensors that do not need any external voltage or current, and make use of the Wiegand effect to generate a consistent pulse every time magnetic field polarity reverses. Wiegand sensors are made by wrapping a coil around a Vicalloy wire core, which, due to the hysteresis inherent in the Wiegand effect, induces a pulse in the coil each time the magnetic polarity of the Vicalloy wire core r…

Key takeaways

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

Reference excerpt

Wiegand sensors are magnetic sensors that do not need any external voltage or current, and make use of the Wiegand effect to generate a consistent pulse every time magnetic field polarity reverses. Wiegand sensors are made by wrapping a coil around a Vicalloy wire core, which, due to the hysteresis inherent in the Wiegand effect, induces a pulse in the coil each time the magnetic polarity of the Vicalloy wire core reverses. They can be used in a range of magnetic sensing applications and have the additional advantage that the energy of each pulse can be harvested.

Energy harvesting The consistency of the pulses produced by Wiegand sensors can also be used to provide energy for ultra-low power electronics to be operated using a single pulse. In addition, successive pulses can be stored to offset energy demand of low-power energy circuits. Alternatively, the pulses can be used to trigger, or ‘wake-up’, intermittently powered electronic circuits. In certain applications, both functions of the pulses (magnetic sensing and energy harvesting) are exploited. The pulse energy is used to power ultra-low power circuitry or ICs which, in turn, use the timing of the pulses to perform calculation tasks (e.g. count event data).

Applications Typical applications fall into three main categories; pulse generation applications, power transmission applications and combined sensing and energy harvesting applications.

Pulse generation As a reliable source of consistently timed pulses, Wiegand sensors are used in industrial and commercial flow-metering applications (e.g. water and gas), and also to calculate rotation speed in tachometers (e.g. high-speed trains).

Power transmission By placing the Wiegand sensor within an oscillating electro-magnetic fields (e.g. from a Helmholtz coil), Wiegand sensors can be used to provide energy for low power applications in environments where high frequency transmission is challenging (e.g. transcutaneous power for medical devices).

Sensing and energy harvesting Wiegand sensors are commonly used in ‘Batteryless’ rotary encoder technology for self-powered revolution counting. Harnessing both the timing of the pulses and the pulse energy, such rotary encoders provide reliable multiturn counting even in the absence of external power or batteries.

References

Illustrations

Worked examples

Example 1 — a first encounter with Wiegand sensor

Start with the simplest possible case. Write down what Wiegand sensor 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 Wiegand sensor 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 Wiegand sensor 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 Wiegand sensor

In research: Wiegand sensor 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 Wiegand sensor 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: Wiegand sensor is common in secondary-school and first-year university syllabi. It links to neighbouring topics Magnetic devices, so understanding it makes those chapters shorter.
In everyday life: Look for Wiegand sensor 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 Wiegand sensor in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Wiegand sensor 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 Wiegand sensor out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Wiegand sensor in simple terms?

Why does Wiegand sensor 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 Wiegand sensor?

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 Wiegand sensor.