Dynamic Loudspeaker Principle

A current-carrying wire in a magnetic field experiences a magnetic force perpendicular to the wire.

An audio signal source such as a microphone or recording produces an electrical "image" of the sound. That is, it produces an electrical signal that has the same frequency and harmonic content, and a size that reflects the relative intensity of the sound as it changes. The job of the amplifier is to take that electrical image and make it larger -- large enough in power to drive the coils of a loudspeaker. Having a "high fidelity" amplifier means that you make it larger without changing any of its properties. Any changes would be perceived as distortions of the sound since the human ear is amazingly sensitive to such changes. Once the amplifier has made the electrical image large enough, it applies it to the voice coils of the loudspeaker, making them vibrate with a pattern that follows the variations of the original signal. The voice coil is attached to and drives the cone of the loudspeaker, which in turn drives the air. This action on the air produces sound that more-or-less reproduces the sound pressure variations of the original signal.
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nokia secret codes

*3370# This Nokia code activates Enhanced Full Rate Codec (EFR)–Your Nokia cell phone uses the best sound quality but talk time is reduced my approx. 5%

#3370# Deactivate Enhanced Full Rate Codec (EFR) .

*#4720# Activate Half Rate Codec–Your phone uses a lower quality sound but you should gain approx 30% more Talk Time.

*#4720# With this Nokia code you can deactivate the Half Rate Codec.

*#0000# Displays your phones software version, 1st Line : Software Version, 2nd Line : Software Release Date, 3rd Line : Compression Type .

*#9999# Phones software version if *#0000# does not work.

*#06# For checking the International Mobile Equipment Identity (IMEI Number) .

#pw+1234567890+1# Provider Lock Status. (use the“*”button to obtain the“p,w”and“+”symbols)

#pw+1234567890+2# Network Lock Status. (use the“*”button to obtain the“p,w”and“+”symbols) .

#pw+1234567890+3# Country Lock Status. (use the“*”button to obtain the“p,w”and“+”symbols)

*#21# This phone code allows you to check the number that“All Calls”are diverted to.

*#2640# Displays phone security code in use .

*#30# Lets you see the private number.

*#43# Allows you to check the“Call Waiting”status of your cell phone.

*#61# Allows you to check the number that“On No Reply”calls are diverted to .

*#62# Allows you to check the number that“Divert If Unreachable (no service)”calls are diverted to*#67# Allows you to check the number that“On Busy Calls”are diverted to

*#67705646# Phone code that removes operator logo on 3310&3330

*#73# Reset phone timers and game scores.

*#746025625# Displays the SIM Clock status, if your phone supports this power saving feature“SIM Clock Stop Allowed”, it means you will get the best standby time possible .

*#7760# Manufactures code.

*#7780# Restore factory settings.

*#92702689# Displays–1.Serial Number, 2.Date Made, 3.Purchase Date, 4.Date of last repair (0000 for no repairs), 5.Transfer User Data. To exit this mode you need to switch your phone off then on again.

*#94870345123456789# Deactivate the PWM-Mem**21*number# Turn on“All Calls”diverting to the phone number entered.

**61*number# Turn on“No Reply”diverting to the phone number entered .

**67*number# Turn on“On Busy”diverting to the phone number entered . 12345 This is the default security code . press and hold  # Lets you switch between lines

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NOTE:- These cods r working in nokia s60 devices according to their versions

Microsoft Excel Shortcuts

MS EXCEL Shortcuts:-
Shortcut Keys Description
F2 Edit the selected cell.
F5 Go to a specific cell. For example, C6.
F7 Spell check selected text or document.
F11 Create chart.
Ctrl + Shift + ; Enter the current time.
Ctrl + ; Enter the current date.
Alt + Shift + F1 Insert New Worksheet.
Shift + F3 Open the Excel formula window.
Shift + F5 Bring up search box.
Ctrl + A Select all contents of the worksheet.
Ctrl + B Bold highlighted selection.
Ctrl + I Italic highlighted selection.
Ctrl + K Insert link.
Ctrl + U Underline highlighted selection.
Ctrl + 5 Strikethrough highlighted selection.
Ctrl + P Bring up the print dialog box to begin printing.
Ctrl + Z Undo last action.
Ctrl + F9 Minimize current window.
Ctrl + F10 Maximize currently selected window.
Ctrl + F6 Switch between open workbooks / windows.
Ctrl + Page up Move between Excel work sheets in the same Excel document.
Ctrl + Page down Move between Excel work sheets in the same Excel document.
Ctrl + Tab Move between Two or more open Excel files.
Alt + = Create a formula to sum all of the above cells
Ctrl + ' Insert the value of the above cell into cell currently selected.
Ctrl + Shift + ! Format number in comma format.
Ctrl + Shift + $ Format number in currency format.
Ctrl + Shift + # Format number in date format.
Ctrl + Shift + % Format number in percentage format.
Ctrl + Shift + ^ Format number in scientific format.
Ctrl + Shift + @ Format number in time format.
Ctrl + Arrow key Move to next section of text.
Ctrl + Space Select entire column.

Shift + Space Select entire row.

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How to Create your own font in xp?

Jst goto:- > start
> run
> type eudcedit
> try to making new fonts
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Difference Between 3G Handsets

Basically 3G handsets are based on HSDPA & WCDMA.
Here's the difference between HSDPA & WCDMA:-

WCDMA stands for Wideband Code Division Multiple Access.
HSDPA (High Speed Downlink Packet Access)

1. WCDMA is commonly referred to as 3G, while HSDPA is commonly referred to as 3.5G.

2. HSDPA provides much higher data rates compared to WCDMA.

3. HSDPA has lower latency times compared to WCDMA.

4. HSDPA has Fast Packet Scheduling and AMC, features that are absent in WCDMA.

5. HSDPA allowed speeds above 384kbps, the most notable of which is 3.6Mbps and 7.2Mbps,      Whereas WCDMA networks were only capable of reaching speeds of 384kbps
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