Tangent Galvanometer
Product Code : EL-LM-10393
Quick answer: The Tangent Galvanometer is an instrument based on the tangent law of magnetism, used to measure small currents and to find the horizontal component of the Earth's magnetic field or the reduction factor of the coil. It has 2, 50 and 500 turn windings on a 162.5 mm Bakelite bobbin and a 100 mm dial. Lab Exports manufactures it in Delhi for schools, colleges and universities.
Specifications
| Component | Specification |
|---|---|
| Principle | Tangent law of magnetism |
| Coil windings | Three: 2, 50 and 500 turns, 4 terminals |
| Coil bobbin | Non-magnetic Bakelite, about 162.5 mm diameter |
| Coil mounting | Rotates on a vertical axis through its centre |
| Dial | Aluminium, 100 mm diameter, graduated 0-90° four times |
| Needle | Agate-centred magnetic needle |
| Reading aid | Anti-parallax mirror |
| Base | Non-magnetic metal tripod with levelling screws |
How the tangent galvanometer experiment is done
A current I in a circular coil of n turns and radius r produces a field B = mu0 n I / (2r) at its centre, perpendicular to the plane of the coil. With the coil set in the magnetic meridian, this field acts at right angles to the horizontal component BH of the Earth's field, and the needle settles at an angle theta where B = BH tan theta. The current is therefore I = K tan theta, where K = 2r BH / (mu0 n) is the reduction factor.
- Level the tripod base with the levelling screws so the needle swings freely.
- Turn the coil about its vertical axis until its plane lies in the magnetic meridian and the needle reads 0-0 on the dial.
- Connect the chosen winding in series with a battery, rheostat, ammeter and reversing key.
- Adjust the current for a deflection near 45 degrees, reading both ends of the pointer against the mirror to avoid parallax.
- Reverse the current, read again and average the four readings before calculating K or BH.
The three windings let one instrument handle different current levels: the 500-turn winding gives a large deflection for small currents, while the 2-turn winding suits larger ones.
Key features
- Three windings of 2, 50 and 500 turns brought out to 4 terminals.
- Non-magnetic Bakelite bobbin of about 162.5 mm diameter.
- Coil rotates on a vertical axis for setting in the magnetic meridian.
- Aluminium dial of 100 mm, graduated 0-90° four times, with an anti-parallax mirror.
- Agate-centred magnetic needle for a free, low-friction swing.
- Non-magnetic tripod base with levelling screws.
Documentation and supply
Installation instructions and a manual are supplied with the apparatus. Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the Tangent Galvanometer 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.
Related Lab Meters products
- Basic Meter (EL-LM-10392)
- Ohms Law Apparatus (EL-LM-10394)
- Ballistic Galvanometer (EL-LM-10391)
- Galvanometer EDSPOT (EL-LM-10390)
- Demonstration Meter Interscale (EL-LM-10389)
- Demonstration Meter Vertical (EL-LM-10388)
The full range is in the Lab Meters section of the Physics Lab range.
Frequently asked questions
What is measured with a tangent galvanometer?
It measures small currents through I = K tan theta; in the laboratory it is used to find the reduction factor K of the coil and the horizontal component of the Earth's magnetic field.
Why is a deflection near 45 degrees preferred?
The relative error in tan theta is smallest near 45 degrees, so readings taken there give the most reliable value of the current or of BH.
What is the price of the Tangent Galvanometer?
Prices are not published on the website. Add the Tangent Galvanometer to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-LM-10393 and the quantity, to receive a quotation.
Does Lab Exports manufacture the Tangent Galvanometer?
Yes. Lab Exports manufactures the Tangent Galvanometer at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-LM-10393.
Request a quote
Email [email protected] with the house code EL-LM-10393 and the quantity, or add the Tangent Galvanometer to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
