SciMed
Helmholtz Galvanometer
Helmholtz Galvanometer
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Twin-coil tangent galvanometer for physics education and undergraduate labs. Two equal coaxial coils in Helmholtz configuration produce a highly uniform axial magnetic field at the midpoint, where a jeweled magnetic compass reads deflection. Ideal for verifying the tangent law and mapping the horizontal component of Earth's magnetic field.
What you get
- Two equal coaxial copper-wound coils mounted at a separation equal to the coil radius (Helmholtz configuration)
- Jeweled permanent-magnet compass housed in a brass cup at the exact geometric midpoint
- Sturdy wooden base with binding-post terminals for external DC source (typically 1.5-6 V battery)
- Included instruction card covering tangent law derivation and the standard classroom experiment
Classroom experiments this device supports
- Verify the tangent law — measure compass deflection versus known current to confirm tan θ ∝ I
- Determine the horizontal component of Earth's magnetic field (BH) — the classic undergraduate physics experiment
- Study field uniformity in a Helmholtz pair — compare field strength at center versus off-axis
- Introduce the Biot-Savart law in an applied setting
Specifications
| Configuration | Helmholtz — two equal coaxial coils, separation = coil radius |
| Coil winding | Insulated copper wire on non-magnetic former |
| Compass | Jeweled permanent-magnet needle in brass cup, mounted at midpoint |
| Base | Polished hardwood with binding-post terminals |
| Recommended source | Regulated DC, 0-6 V (rheostat + ammeter recommended) |
| Best suited for | Grades 11-12, undergraduate physics, engineering demo labs |
Frequently asked questions
Is this a true Helmholtz configuration?
Yes. The two coils are equal, coaxial, and separated by exactly the coil radius — the geometry that produces uniform axial field near the midpoint.
What power source do I need?
A regulated DC source of 0-6 V paired with a rheostat and ammeter. A standard physics-lab power supply or dry cells work fine. Not included.
Does the compass come pre-calibrated?
The needle is jeweled and free-swinging. Level the base and align the coil plane with the magnetic meridian before each measurement — standard procedure covered in the instruction card.
Can I use this to measure Earth's magnetic field?
Yes — this is the classic tangent-galvanometer experiment for determining the horizontal component (BH) of Earth's field.
Do you accept school purchase orders?
Yes. Email a PO to sales@scimedstore.com with your institution's tax-exempt certificate.
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