Is the most popular because they are cheap can be seen by the general public to work. Caused by the movement of the coil wire to cut to a magnetic field, thus causing a laeoklai induced tone out.
Is very popular because it is cheap. Can be seen by the general public to work caused by the movement of the coil to cut the magnetic field and thus induce a signal out.
The most popular because it is cheaper. Can be seen by the general public and work caused by the movement of the coil to cut with a magnetic field can cause induction into audio signals.