Brass Four Way Plug Key
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Product Code : SCL-EAE-12120
Brass Four Way Plug Key (SKU SCL-EAE-12120) is a plug-operated switch with four brass blocks arranged in a circle, used to route current along different paths or reverse its direction by moving two plugs. Physics teachers use it in Class 12 and college electricity and magnetism practicals such as tangent galvanometer work. It is produced at the Science Lab Supplies factory, Plot 448, HSIIDC Industrial Area, Saha, Ambala, India, and the company, as manufacturer, supplies it directly to schools, colleges, tender contractors and distributors.
Specifications
The table below gives each specification on its own row. In short, solid high-conductivity brass blocks form a four-way circular commutator on a heavy insulated Bakelite base, with two interlapped brass plugs on insulated handles and four heavy brass binding posts, rated at 24 V AC/DC and 5 A.
| Specification | Value |
|---|---|
| SKU | SCL-EAE-12120 |
| Configuration | 4-way circular commutator matrix |
| Block material | Solid high-conductivity brass |
| Base material | Heavy-duty insulated Bakelite |
| Plugs | 2 x interlapped tapered brass plugs |
| Plug handles | Insulated, knurled ebonite or high-impact plastic |
| Terminals | 4 x heavy brass binding posts |
| Maximum voltage | 24 V AC / DC |
| Maximum current | 5 A |
| Documentation | Schematic sheet showing current routing options |
| Manufacturer | Science Lab Supplies, Saha, Ambala, Haryana |
| Country of origin | India |
Applications and Experiments for the Four Way Plug Key
Inserting the plugs into chosen gaps closes particular paths; moving them to the other pair of gaps reverses the current or diverts it to another branch. Because no rewiring is needed, readings stay quick and repeatable, which makes the key a practical piece of physics lab equipment in India for electricity and magnetism benches.
- Class 12 and B.Sc. physics: reversing current in the Tangent Galvanometer and deflection magnetometers to remove orientation bias.
- Routing current through alternative paths in Ohm's law work with the Ohms Law Apparatus.
- Wheatstone bridge experiments, isolating or switching a connected meter.
- Demonstrating switching, network balancing and bridge isolation.
Switch the supply off before rewiring the terminals, keep within 5 A, and never connect the key to mains.
Standard Scope of Supply
The set includes the Brass Four Way Plug Key base assembly with its four binding posts, two precision-machined brass plugs with non-conductive handles, and a schematic diagram sheet that shows the current-routing options. Leads, meters and power sources are quoted separately where required.
Packing, MOQ and Lead Time
Quotations cover anything from a single key to a full set for each electricity bench. Science Lab Supplies lists the packing, delivery time and price for the requested quantity, and other keys, galvanometers or resistance boxes needed for the same practicals can be added to that quotation.
Registered with an Importer-Exporter Code, Science Lab Supplies can ship to buyers in Egypt, Iraq, Nigeria, Kenya, Ghana and Ethiopia. The business is registered under Udyam as a manufacturing enterprise (UDYAM-HR-01-0014546) and for GST (GSTIN 06ADEPJ0574F2ZU). Enquiries reach the team from the contact page or the enquiry cart, and the lab tender page covers tender requirements.
Frequently Asked Questions
How is it used as a current-reversing commutator?
Connect the supply to one pair of opposite blocks and cross-connect the remaining terminals to the load. Placing the two plugs in one diagonal pair of gaps gives one direction; moving them to the other pair reverses it.
What are the voltage and current ratings?
The key is rated for low-voltage educational circuits up to 24 V AC or DC and a maximum of 5 A. It should never be wired to household mains or other high-voltage supplies.
What should be done if the plugs feel loose?
Check the gaps for dust or oxide film and wipe the tapered surfaces with a dry, lint-free cloth. Keep the original plugs with their own base, because the interlapped fit is matched to that assembly.
Is Science Lab Supplies the manufacturer or a trader?
It is the manufacturer. Science Lab Supplies machines and assembles the plug key at its own facility in Saha, Ambala, India, so buyers work with the producer and receive factory quotations.
Related Keys and Electricity Apparatus
The products below share the four-way key's role in electricity practicals: other keys for making, switching or reversing current, plus the resistance boxes and meters wired alongside them. They belong to the Electrical and Electronics and Lab Meters ranges and can all go on one quotation for an electricity bench.
- Reversing Key Commutator For Lab — lever-type reversing switch with a neutral position, 3 A.
- Brass Two Way Plug Key Switch — three brass blocks and one plug for two-branch routing.
- Brass One Way Plug Key — makes or breaks a single circuit path.
- Tapping Key Physics Lab — spring-return key for momentary contact.
- Resistance Box Plug Type (Constantan / Manganin Coil) — plug-type box with brass blocks and wound coils.
- Galvanometer 30-0-30 mA — moving coil meter with colour-coded 4 mm sockets.
- Voltmeter — DC meter on a bakelite or acrylic stand with lock-type terminals.
Browse the full Electrical and Electronics range, the Lab Meters range for galvanometers and meters, or all physics lab equipment.
Last updated: 9 October 2026
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