introduction to electrostatic speaker,working principle,construction

2. Introduction To Electrostatic
Speaker

3. 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
D e p a r t m e n t o f E l e c t r i c a l E n g i n e e r i n g , Wa h E n g i n e e r i n g
C o l l e g e
Wa h C a n t t .

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

5. Introduction
 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.

6. Introduction of ESL
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.

7. Introduction
 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.

8. Introduction To ESL
 Electrostatic force is given by
 Where Q1 and Q 2 are the charges, r is the distance
between them, and k is the proportionality constant.

9.  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.
Principle of ESL

10.  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.
Principle of ESL

11. ASIF WAHAB
UW-15-EE-BSC-82

12. Construction of ESL
 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

13. Construction of ESL
 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

14. Circuit Diagram

15. RANA UTBAN
UW-15-EE-BSC-016

16. Working of ESL
 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

17. Working of ESL
 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

18. Working of ESL
 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.

19. Graphical Explanation of ESL

20. MUHAMMAD SUBHAN
UW-15-EE-BSC-010

21. Advantage of ESL
 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.

22. Advantage of ESL
 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.

23. Disadvantage of ESL
 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

24. Conclusion
 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.

25. References
1. https://www.martinlogan.com/learn/electrostatic-
speakers.php
2. http://hackaday.com/2016/08/03/electrostatic-
loudspeakers-high-end-hifi-you-can-build-yourself/
3. https://en.wikipedia.org/wiki/Electrostatic_loudspe
aker
4. http://www.audiodesignguide.com/esl/esl.html