Equlizer Project For Controlling wide band of Frequency.

Here is the Preamplifier unit for Sub-woofer and Central speaker.

For the separate channel of the Treble and bass sound, They have variable resistor for controlling the gain







 For controlling each channel such as Balance, Volume, Bass and Treble, they have included quad OP-Amp per each section using UPC4558

The variable resistors are enabled dual controlling functionality for the Bass and treble sound. Entirely four variable resistors are used for controlling left and right channel.

Seven Band Graphic Equalizer system for Front speakers.

Back side of PCB

By using few comparator, we can make the controller with wide band of frequency.

Single PCB for one channel

double PCB for stereo

This circuit can control only 7 band of the sound. For buffer of the sound, they have used NE5534 op-Amp.

Multi Layer Management with Smooth Glass Effect in Adobe Photoshop CS3

Updated Library management System-Staff only

Form Validation

 -- NON EMPTY FIELDS VALIDATION

 --Here is the script for validate them all--

 <script type='text/javascript'>
function notEmpty(elem, helperMsg){
	if(elem.value.length == 0){
		alert(helperMsg);
		elem.focus();
		return false;
	}
	return true;
}
</script>

 --This is the code for controllers in the form--

<form>
Required Field: <input type='text' id='req1'/>
<input type='button' 
	onclick="notEmpty

(document.getElementById('req1'), 'Please Enter a Value')"
	value='Check Field' />
</form>

-- ALL NUMBERS ONLY FIELDS 

<script type='text/javascript'>
function isNumeric(elem, helperMsg){
	var numericExpression = /^[0-9]+$/;
	if(elem.value.match(numericExpression)){
		return true;
	}else{
		alert(helperMsg);
		elem.focus();
		return false;
	}
}
</script>
<form>
Numbers Only: <input type='text' id='numbers'/>
<input type='button' 
	onclick="isNumeric

(document.getElementById('numbers'), 'Numbers Only Please')"
	value='Check Field' />
</form> 

--ALL LETTERS CHECKING FIELDS

<script type='text/javascript'>
function isAlphabet(elem, helperMsg){
	var alphaExp = /^[a-zA-Z]+$/;
	if(elem.value.match(alphaExp)){
		return true;
	}else{
		alert(helperMsg);
		elem.focus();
		return false;
	}
}
</script>
<form>
Letters Only: <input type='text' id='letters'/>
<input type='button' 
	onclick="isAlphabet

(document.getElementById('letters'), 'Letters Only Please')"
	value='Check Field' />
</form> 

--FIELD SIZE VALIDATING

<script type='text/javascript'>
function lengthRestriction(elem, min, max){
	var uInput = elem.value;
	if(uInput.length >= min && uInput.length <= max){
		return true;
	}else{
		alert("Please enter between " +min+ " and " +max+ " characters");
		elem.focus();
		return false;
	}
}
</script>
<form>
Username(6-8 characters): <input type='text' id='restrict'/>
<input type='button' 
	onclick="lengthRestriction

(document.getElementById('restrict'), 6, 8)"
	value='Check Field' />
</form>

--SELECTION BOX VALUE CHECKING

<script type='text/javascript'>
function madeSelection(elem, helperMsg){
	if(elem.value == "Please Choose"){
		alert(helperMsg);
		elem.focus();
		return false;
	}else{
		return true;
	}
}
</script>
<form>
Selection: <select id='selection'>
<option>Please Choose</option>
<option>CA</option>
<option>WI</option>
<option>XX</option>
</select>
<input type='button' 
	onclick="madeSelection

(document.getElementById('selection'), 'Please Choose Something')"
	value='Check Field' />
</form> 

--E-MAIL FIELDS CHECKING

<script type='text/javascript'>
function emailValidator(elem, helperMsg){
	var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;
	if(elem.value.match(emailExp)){
		return true;
	}else{
		alert(helperMsg);
		elem.focus();
		return false;
	}
}
</script>
<form>
Email: <input type='text' id='emailer'/>
<input type='button' 
	onclick="emailValidator1

(document.getElementById('emailer'), 'Not a Valid Email')"
	value='Check Field' />
</form> 

--ALL FORM EVENTS VALIDATING

--HTML CODE

<form onsubmit='return formValidator()' >
First Name: <input type='text' id='firstname' /><br />
Address: <input type='text' id='addr' /><br />
Zip Code: <input type='text' id='zip' /><br />
State: <select id='state'>
	<option>Please Choose</option>
	<option>AL</option>
	<option>CA</option>
	<option>TX</option>
	<option>WI</option>
</select><br />
Username(6-8 characters): <input type='text' id='username' /><br />
Email: <input type='text' id='email' /><br />
<input type='submit' value='Check Form' /><br />
</form>

--JAVASCRIPT CODE 

function formValidator(){
	// Make quick references to our fields
	var firstname = document.getElementById('firstname');
	var addr = document.getElementById('addr');
	var zip = document.getElementById('zip');
	var state = document.getElementById('state');
	var username = document.getElementById('username');
	var email = document.getElementById('email');
	
	// Check each input in the order that it appears in the form!
	if(isAlphabet(firstname, "Please enter only letters for your name")){
		if(isAlphanumeric(addr, "Numbers and Letters Only for Address")){
			if(isNumeric(zip, "Please enter a valid zip code")){
				if(madeSelection(state, "Please Choose a State")){
					if(lengthRestriction(username, 6, 8)){
						if(emailValidator

(email, "Please enter a valid email address")){
							return true;
						}
					}
				}
			}
		}
	}
	
	
	return false;
	
}

Source Link http://www.tizag.com/javascriptT/javascriptform.php