1. I have since realised that I was describing the special case of bifilar windings. 2. Wire can be purchased in bifilar form, usually as different colored enameled wire bonded together. 3. Each cell consisted of a wooden dowel with a bifilar winding of copper and zinc wires. 4. Bifilar coils impose an inductance in the common mode, but impose no inductance in the differential mode.5. In engineering, the word " bifilar " describes wire which is made of two filaments or strands. 6. Because of their proximity, the wires of the bifilar coil both " see " the same stray magnetic flux. 7. Klinkerfues had developed a bifilar -hygrometer which was widely used but did not prove in laymen's hands. 8. A "'bifilar coil "'is an electromagnetic coil that contains two closely spaced, parallel windings. 9. Other techniques employ bifilar winding, or a flat thin former ( to reduce cross-section area of the coil ). 10. "' Ayrton-Perry winding "'is a type of bifilar winding pattern used in winding wire on forms to make electronic components.