In bifilar or quadrifilar implementations, broadside circularly polarized radiation can be realized. German physicist Wilhelm Eduard Weber made use of the bifilar coil in his 1848 electrodynamometer. This was possibly the first time bifilar wound coils had been combined with transistor electronics. Wire can be purchased in bifilar form, usually as different colored enameled wire bonded together. A bifilar coil is an electromagnetic coil that contains two closely spaced, parallel windings. In engineering, the word "bifilar" describes wire which is made of two filaments or strands.