Spark inductor (Rühmkorff coil)

Product Code : SCL-EI-10688

The Spark Inductor (Rühmkorff Coil) is a physics laboratory apparatus used to demonstrate electromagnetic induction, high-voltage pulse generation, spark discharge, and transformer action under trained teacher supervision.

Quick Answer: A Spark Inductor (Rühmkorff Coil) uses a make-and-break primary current and a stepped-up secondary winding to convert a low-voltage input into a visible high-voltage spark, demonstrating electromagnetic induction and transformer action. It must be operated only by a teacher or trained laboratory instructor, since the secondary output can produce high voltage and students should never touch the terminals during operation.

Important: This apparatus is for supervised educational demonstration only. Students should observe rather than operate it directly, and it should never be connected to mains electricity unless specifically rated for that input.

Key Features

• Induction coil demonstration: shows how changing current in a primary coil can induce a higher voltage in a secondary coil
• Visible spark output: helps students observe spark discharge in a controlled laboratory setting
• Electromagnetism teaching aid: supports lessons on induction, transformers, magnetic flux, and voltage step-up action
• Useful for practical physics: suitable for teacher-led demonstrations in schools, colleges, and STEM laboratories
• Compatible with lab instruments: can be used with approved electronic instruments and low-voltage power sources where rated
• Reusable classroom apparatus: designed for repeated demonstrations when operated within confirmed ratings
• Safety-focused handling: requires trained supervision because the secondary output may produce high voltage

Technical Specifications

• Inspect the coil, terminals, leads, and spark gap before connecting any power source.
• Connect only the rated low-voltage input supply specified for the model.
• Adjust the spark gap gradually if adjustable terminals are provided.
• Switch on the supply briefly and observe the spark discharge from a safe distance.
• Switch off the supply before changing connections, touching terminals, or storing the unit.

Safety note: A spark inductor can generate high voltage at the output. Do not touch the terminals during operation, do not connect it to mains electricity unless specifically rated, and use suitable safety protective wears during supervised demonstrations. Students should observe under supervision only — the apparatus should be operated solely by a teacher or trained laboratory instructor.

Care and Maintenance

• Keep the coil dry and free from dust, moisture, and conductive contamination.
• Store the apparatus in a dry cabinet after the unit is fully switched off and discharged.
• Do not operate the coil continuously beyond the confirmed duty cycle.
• Replace damaged leads, cracked insulation, or loose terminals before further use.

Two Ways to Produce High-Voltage Sparks for Classroom Demonstrations

The Spark Inductor (Rühmkorff Coil) produces its high-voltage spark through electromagnetic induction — a changing primary current stepping up voltage in a secondary winding, the same principle behind a transformer. This is a different mechanism from the Influence Machine or the Van de Graaff Generator, both of which build static charge through electrostatic induction and friction. Schools teaching both induction mechanisms side by side often pair this apparatus with the Coil with 400 Turns and Mains Coil with 600 Turns to build a complete transformer and induction demonstration module.

Frequently Asked Questions

What is a Spark Inductor (Rühmkorff Coil) used for?
A Spark Inductor (Rühmkorff Coil) is used to demonstrate electromagnetic induction, transformer action, and high-voltage spark discharge in physics laboratories.

Is a Rühmkorff coil suitable for school physics labs?
Yes. It is suitable for school and college physics demonstrations when operated by a trained teacher using the correct rated power source.

Does the spark inductor produce high voltage?
Yes. The secondary output can produce high voltage for spark discharge demonstrations, so students should not touch the terminals during use.

What concepts does this apparatus teach?
It teaches electromagnetic induction, magnetic flux change, voltage step-up action, spark discharge, and make-and-break current behaviour.

Can students operate the apparatus directly?
No. Students should observe under supervision. The apparatus should be operated only by a teacher or trained laboratory instructor.

Related Products

• Coil with 400 Turns
• Mains Coil with 600 Turns
• Influence Machine

Request a Quote

For pricing, bulk institutional orders, or tender submissions for the Spark Inductor (Rühmkorff Coil), please contact us or view our lab equipment tender page.

Last updated: September 2026