Electrostatic speaker

introduction to electrostatic speaker,working principle,construction

1. Introduction To Electrostatic S peaker

2. Group Members Ibrar Saqib UW-15-EE-BSC-046 Muhmmad Subhan UW-15-EE-BSC-010 Rana Utban UW-15-EE-BSC-016 Asif Wahib UW-15-EE-BSC-082 Department of Electrical Engineering, Wah Engineering College Wah Cantt .

3. Introduction Principal of Electrostatic Speaker Construction of Electrostatic Speaker Circuit diagram Working of Electrostatic Speaker Graphical Explanation of ESL Advantage Disadvantage Application Conclusion

4. Electrostatic mean stationary charges where as Speaker is a an electro acoustic transducer; which converts an electrical audio signal into a corresponding sound An electrostatic Speaker (ESL) is a speaker design in which sound is generated by the force exerted on a membrane suspended in an electrostatic field.

5. Electrostatic The study of electric charges at rest is called electrostatics. Its other name is ‘static electricity’. Electrically charged objects have several important characteristics: Like charges repel one another; that is, positive repels positive and negative repels negative. Unlike charges attract each another; that is, positive attracts negative.

6. Electrostatics is the study of forces between charges, as described by Coulomb's Law. Coulomb's law states that: The magnitude of the electrostatic force of attraction between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.

7. Electrostatic force is given by Where Q 1 and Q 2 are the charges, r is the distance between them, and k is the proportionality constant.

8. Electrostatic Speaker is purely based on electrostatic force. ESLs are simply (coulomb Law) a way to keep electric charges separated but close together so they can do the work of moving a plastic film to produce sound. 

9. The usual construction technique is to place a tight plastic film (the diaphragm) with an electric charge between two charged conductors (called stators) on which the charges alternate.  At one instant, the diaphragm is driven towards one of the stators, then when the polarity of the charge on the conductors reverses, the diaphragm is driven toward the other conductor this result is sound. 

10. Asif Wahab UW-15-EE-BSC-82

11. Electrostatic speaker consist of three Layers Three layers. Two outer layers are stators and are fixed in place. Inner layer called diaphragm and is flexible film

12. The speakers use a thin flat diaphragm usually consisting of a plastic sheet coated with a conductive material such as graphite sandwiched between two electrically conductive grids, with a small air gap between the diaphragm and grids

13. Rana Utban UW-15-EE-BSC-016

14. When the speaker is operating, the diaphragm is charged to a fixed positive voltage by a high-voltage power supply, creating a strong electrostatic field around it The stators, meanwhile, are connected to the audio system's amplifier through a step-up transformer

15. Step-up Transformer converts the amplifier's output to a pair of high-voltage signals of equal strength but opposite polarity. So as the charge on one stator grows increasingly positive, the charge on the other grows more negative by exactly the same amount. Because like charges repel and opposite charges attract, the diaphragm's positive charge will force it to move forward or backward depending on the stator charges

16. When the front stator's charge is negative and the back stator's positive, the diaphragm will be pulled from the front and pushed from the back and therefore move forward. The stronger the charges on the stators, the greater the diaphragm displacement. In this way ESL Produce sound.

17. Muhammad Subhan UW-15-EE-BSC-010

18. Musical transparency can be better than in electrodynamics speakers because the radiating surface has much less mass than most other drivers and is therefore far less capable of storing energy to be released later. For example, typical dynamic speaker drivers can have moving masses of tens or hundreds of grams whereas an electrostatic membrane only weighs a few milligrams, several times less than the very lightest of electrodynamics speaker.

19. Advantages of electrostatic loudspeakers include levels of distortion one to two orders of magnitude lower than conventional cone drivers in a box The extremely light weight of the diaphragm which is driven across its whole surface, and exemplary frequency response (both in amplitude and phase) because the principle of generating force and pressure is almost free from resonances unlike the more common electrodynamics driver.

20. Cannot produce the lower frequency sounds Very, very sensitive to humidity changes and can lead to costly repairs Arcing is very common, where a large amounts of electricity is released at one point burning a hole in the stator

21. Electrostatic speaker is work on the principle of Electrostatic Force It is very sample in construction other than conventional speaker Thin, late and smart and stylish design due to flate thin diaphram . It required high step-up voltage and high biase voltage such as 4-6kv DC,there it is very expensive.

22. References https://www.martinlogan.com/learn/electrostatic-speakers.php http://hackaday.com/2016/08/03/electrostatic-loudspeakers-high-end-hifi-you-can-build-yourself/ https://en.wikipedia.org/wiki/Electrostatic_loudspeaker http://www.audiodesignguide.com/esl/esl.html

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