Reversing Key Commutator

Last updated: September 2026

Quick Answer: The Reversing Key Commutator is a physics laboratory switching accessory that reverses the direction of current through a selected circuit branch without students having to manually swap connecting wires. It is used in electricity and magnetism experiments – such as tangent galvanometer and magnetic-field investigations – that require repeatable current reversal so readings can be compared for both directions. LabEquip supplies this commutator key as part of its Keys and Switches range for schools, colleges and technical laboratories.

Product Description

This Reversing Key Commutator from LabEquip lets students change the direction of current flow through a connected section of a circuit simply by moving the key, instead of disconnecting and reversing wires by hand. In a typical reversing arrangement, the internal contacts are wired so that one key position sends current one way through the load, and the other position sends it the opposite way.

This makes it especially useful in experiments involving tangent galvanometers, magnetic-field measurements and other setups where a reading needs to be taken for current flowing in one direction and then repeated with the current reversed, so students can compare or average the two observations and reduce the effect of any fixed error such as the earth’s magnetic field.

The exact terminal count, contact arrangement, base construction and voltage/current rating were not included in the specification on file for this listing. Institutions who need the precise configuration before finalising a lab equipment order are welcome to confirm details with LabEquip.

What This Key Helps Students Learn

• How a reversing key (commutator) changes the direction of current through a circuit branch.
• Why taking readings with current in both directions helps cancel out fixed background effects, such as in tangent galvanometer experiments.
• How to wire a reversing key correctly into a magnetism or current-electricity circuit.
• The difference between simply switching a circuit on/off and reversing the direction of current through it.
• How averaging readings taken in opposite current directions improves experimental accuracy.

Specifications

Safety Note

Use this key only within its confirmed voltage and current rating, and treat it as a low-voltage educational accessory unless LabEquip explicitly confirms a higher rating for a specific order. Switch the key only with the circuit at rest where possible, and do not touch exposed terminals while current is flowing. Recommended for classroom and laboratory use under teacher or instructor supervision.

Care & Maintenance

• Keep the key’s contacts and terminals clean, dry and free of corrosion.
• Move the reversing lever or plug smoothly, without forcing it between positions.
• Inspect terminal screws and connecting leads for looseness before each practical session.
• Store the commutator in a dry laboratory cabinet, away from moisture that could corrode contacts.

Why Choose LabEquip

LabEquip supplies physics lab keys, switches and current-electricity and magnetism apparatus to schools, colleges and technical institutes across India. Alongside this Reversing Key Commutator, our Keys and Switches range includes the Four Contact Plug Key for multi-point circuits and the Single Circuit Plug Key for simple make/break control.

Frequently Asked Questions

What does a reversing key (commutator) do?
It reverses the direction of current flowing through a selected part of a circuit, without the student needing to physically swap the connecting wires.

Why is current reversal needed in a tangent galvanometer experiment?
Taking readings with the current in both directions and averaging them helps cancel out fixed errors, such as the influence of the earth’s own magnetic field on the compass needle.

What voltage or current rating does this key support?
The exact rating was not confirmed for this listing. Treat it as a low-voltage educational accessory and contact LabEquip for a specific technical rating before ordering.

Is this different from a simple on/off plug key?
Yes. A plug key only opens or closes a circuit, while a reversing key/commutator changes the direction current flows through the circuit while keeping it connected.

Can this be used in other electricity and magnetism experiments beyond the tangent galvanometer?
Yes, any experiment that needs current reversed through a coil, wire or component in a controlled, repeatable way can generally use a reversing key of this type.