Rheostat Constantine (Eureka) Wire
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Product Code : EL-EAE-10287
Quick answer: The constantan (Eureka) wire rheostat is a sliding variable resistor used in school and college circuit experiments to control current or to act as a potential divider. Its oxidised constantan winding sits on a heat-resistant porcelain tube, with a double-contact phosphor-bronze slider, and ratings run from 0.6 to 8 A. Lab Exports manufactures it in Delhi for schools, colleges and universities.
Specifications
| Component | Specification |
|---|---|
| Winding | Electrically oxidised constantan (Eureka) wire |
| Former (pipe) | Special porcelain, heat-resistant and insulated |
| Slider contact | Phosphor bronze, double contact system, running on a sliding rod |
| Slider block | Heavy brass block |
| End supports | Bakelite or aluminium moulded, holding the pipe at each end |
| Terminals | Three brass terminals |
| Current rating | 0.6 A to 8 A, depending on the model |
State the current rating and resistance value required when sending an enquiry.
How the rheostat is used
A rheostat changes the resistance in a circuit by moving a sliding contact along a coil of resistance wire. Connected through one end terminal and the slider terminal, it works as a variable resistance that sets the current in a series circuit, for example when taking a set of current and voltage readings in an Ohm's law experiment. Connected across both end terminals with the output taken from the slider, it becomes a potential divider that gives a smoothly variable voltage from a fixed supply.
Constantan, the copper-nickel alloy sold as Eureka wire, is chosen because its resistance changes very little with temperature. The setting therefore stays steady as the coil warms under load, which matters when readings must hold over a full experiment.
- Choose a rating whose maximum current is above the highest current expected in the circuit.
- For current control, connect one end terminal and the slider terminal in series with the load.
- For a potential divider, connect the supply across both end terminals and take the output between one end and the slider.
- Start with the slider at the maximum-resistance end, switch on, then move it slowly to the required reading.
Key features
- Winding of electrically oxidised constantan (Eureka) wire, whose low temperature coefficient keeps the resistance setting steady.
- Heat-resistant, insulated porcelain tube as the former for the winding.
- Phosphor-bronze double-contact slider moving on a sliding rod for even, continuous adjustment.
- Heavy brass slider block for smooth movement and long service life.
- Three brass terminals for use as a variable resistance or as a potential divider.
- Bakelite or aluminium moulded end supports; current ratings from 0.6 A to 8 A.
Documentation and supply
Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the constantan (Eureka) wire rheostat at its works in Laxmi Nagar, Delhi, and supplies it to schools, colleges and universities in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.
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- Rheostat Nichrome Wire Groove Type (EL-EAE-10288)
- Post Office Box Plug Type (EL-EAE-10285)
- Meter Bridge or Wheatstone Bridge with Pencil Jockey (EL-EAE-10289)
- Decade Resistance Box, Dial Type (EL-EAE-10284)
- Potentiometer with Jockey Pencil (EL-EAE-10290)
The full range is in the Electrical and Electronics section of the Physics Lab range.
Frequently asked questions
What current ratings are available for the constantan rheostat?
The rheostat is offered in current ratings from 0.6 A to 8 A. Give the rating and the resistance value needed when sending an enquiry.
Why use constantan (Eureka) wire in a rheostat?
Constantan has a very low temperature coefficient of resistance, so the resistance set on the rheostat drifts very little as the wire warms during an experiment.
Can the rheostat be used as a potential divider?
Yes. With the supply across the two end terminals and the output taken from the slider terminal, it gives a continuously variable voltage.
What is the price of the constantan (Eureka) wire rheostat?
Prices are not published on the website. Add the constantan (Eureka) wire rheostat to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-EAE-10287 and the quantity, to receive a quotation.
Does Lab Exports manufacture the constantan (Eureka) wire rheostat?
Yes. Lab Exports manufactures the constantan (Eureka) wire rheostat at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-EAE-10287.
Request a quote
Email [email protected] with the house code EL-EAE-10287 and the quantity, or add the constantan (Eureka) wire rheostat to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
