There are 140 coils in each Helmholtz coils.
This compact self-contained unit is used to explore electron properties and measure e/m. A vertically oriented vacuum tube containing a trace of inert gas oriented to emit a focused beam of electrons horizontally, creating a visible fine beam.
The tube and base can be rotated about their vertical axis, varying the orientation of the electron beam to a pair of Helmholtz coils. This allows magnetic deflection of the beam to be demonstrated. Circular, helical or undeflected paths can be seen.
Built-in LED indicators show the direction of current flow in the coils and allow students to use the Lorentz relation to show that the electronic charge is negative. A pair of electrode plates is attached to the main electrode assembly to demonstrate electrostatic deflection.
The base of the unit contains a power supply that provides all the required potentials and has built-in panel meters for the coil current and beam accelerating voltage. 110V/60Hz AC. Comes with manual.
There are 140 coils in each Helmholtz coils.