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Electrodynamic transducer. Skizze: Elektrodynamische Wandler. The underlying principle is that of the motor. A conductor through which a current flows is. Download Citation on ResearchGate | Electrodynamic transducer including inset | An electromagnetic transducer has a moving coil, a diaphragm and a magnet. A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another.


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A further disadvantage of the electrostatic type loudspeakers is that electrodynamic transducer present a capacitive and high impedance load to the power source which is very difficult to match.

Electrodynamic transducer | Visaton

Accordingly objects of the present invention are to provide a transducer with a wide and uniform frequency response which utilizes adiaphragm of very low rigidity and relatively low mass, and further to provide a transducer inherently capable of very low nonlinear distortion.

Further objects of the present invention are to provide electrodynamic transducer a transducer which is of simple and very reliable construction not requiring close or precision gaps or other spacings, which does not electrodynamic transducer a polarizing voltage supply, and which lends itself to simple and inexpensive mass production.

The present invention contemplates utilizing a generally planar diaphragm of very low rigidity which has an electrodynamic transducer circuit covering most or all of its area. This circuit is disposed in a magnetic field which is edgewise the diaphragm and which islocally oriented so as to produce aiding forces over the entire diaphragm as'a current is passed through said circuit.

The advantage of this general form of construction is that the driving force is electrodynamic transducer to the diaphragm over a large part electrodynamic transducer its area just as is the air load.

Consequently the diaphragm is not required to possess any great structural rigidity with its attendant parasitic mass. In a preferred embodiment the circuit is constituted by metal foil laminated to a thin plastic film which constitutes the diaphragm.


A preferred method of construction is to laminate the metal foil to the plastic film in solid sheets and then to electrodynamic transducer the unwanted metal electrodynamic transducer preferential etching leaving the desired circuit.

Therefore, it is proposed that the path reverse its direction periodically so as to still cover most or all of the area of the diaphragm. Accordingly, the magnetic field must reverse its direction with the same spatial periodicity so that the forces produced by the instantaneous current flow will be aiding over the entire current path, that is, so that the magnetic field will cross the current path in the same sense throughout its length.

In one aspect the diaphragm is essentially rectangular and the conduction path covers it in parallel strips, each strip being joined at its one end to one electrodynamic transducer strip and at its other end to electrodynamic transducer other adjacent strip, adjacent strips being spaced from one another by a narrow gap.

Correspondingly, magnetic poles may lie along the gap between adjacent strips-and in relatively close relationship to the diaphragm.

USA - Electrodynamic transducer - Google Patents

Adjacent electrodynamic transducer are then of opposite polarity so that there exists a magnetic field, passing edgewise through the diaphragm and across the current path, which reverses direction at every gap between adjacent conducting strips whereby a current through electrodynamic transducer circuit will produce aiding forces over the entire diaphragm.

In a more specific aspect the poles may be those of bars having essentially permanent dipole magnetization and lying along every otherstrip in relatively close spaced relationship to the diaphragm, the bars being polarized edgewise of'the diaphragm and normal to their length, and each bar being magnetized similarly.

A more uniform magnetic field surrounding the conducting path may be obtained if a matching array of mag netic poles is placed on the opposite side of the diaphragm with poles of like polarity facing across the diaphragm.


In'this way the nonlinear distortion due to spatial variation of the magnetic field as the diaphragm vibrates may be minimized. The other ends of these magnets may rest against a structure of magnetically soft material electrodynamic transducer as to complete electrodynamic transducer magnetic circuit with minimum reluctance.


In another embodiment the invention contemplates that the poles electrodynamic transducer the ends of compact rectangular bar magnets lying with their direction of polarization parallel to the plane of the diaphragm whereby the opposite poles lie along adjacent gaps between conducting strips, the magnets and correspondingly rectangular air spaces being arranged in the form ofa checkerboard array.

In this case, magnets in one row, the row direction being normal to the direction of electrodynamic transducer, are magnetized oppositely from those in electrodynamic transducer adjacent row.

US5905805A - Electrodynamic transducer - Google Patents

When this device is used to produce acoustic energy, it is obvious that electrodynamic transducer diaphragm will radiate from both of itssurfaces. Especially at low frequencies where the wave length is large as compared with the dimensions of the transducer, the soundwaves may travel around the edge of the diaphragm and cause destructive interference.

Inorder to avoid this effect it is electrodynamic transducer that thisdevice be used electrodynamic transducer a suitable enclosure for isolating the back radiation or for delaying it so that it appears in phase with the forward radiation.

Such enclosures are well understood in the art and form no part of the present invention.

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It is electrodynamic transducer contemplated that combinations of units ac-' cording to the present invention may be assembled in; order to handle electrodynamic transducer power, or in order to cover a greater range of frequency or, for a given range of frequencies, to minimize Doppler type frequency modulation distortion.