Tuesday, April 22, 2008

VU Meter Circuits and Projects

Here is a collection of web pages of VU Meter projects that helps a newbie getting into the Electronics DIY Hobby Land.

VU Meter Circuits and Projects

A Hobby now in your School days or College can help you build a strong profession later. It is Edutainment that will make productive use of your spare time. Friends can do it as a group, during holidays. Parents should encourage healthy hobbies, as the children will grow in a positive and creative atmosphere.
This is a very eye appealing audio accessory. Displays an approximate output level for each channel of a stereo amplifier. Connects to the speaker terminal; levels are displayed in ten steps. User may select either a moving dot bar appearance. Uses two LM3915 IC's; includes a discussion of measuring audio power.

Saturday, April 19, 2008

The Scots Guide to Electronics

This course is designed to help you learn about components, circuits, and the use of electronics. You can explore the contents in whatever order you wish.The emphasis is on providing information starting at the 'absolute beginners' level, but we hope eventually to provide material of use to anyone interested in electronics and its applications ...

The Scots Guide to Electronics

This section of the Scots Guide deals with Analogue Electronics with a special emphasis on Audio-related topics. There are also some specialist pages on the properties of cables as these relate to audio.

The Scots Guide to Electronics

The First Eleven - Basic electronics courses sometimes make it appear as if electronic engineers have an obsession with voltmeters, batteries, and oscilloscopes. That's because it's often convenient to talk about these when presenting a course at a university, college, or wherever. In reality, the physics and electronics of practical systems like Hi-Fi's, TV's, computers, etc, are much more interesting.

The main components used in electronics are of two general types: passive (e.g. resistors and capacitors) and active (e.g. transistors and integrated circuits). The main difference between active and passive components is that active ones require to be powered in some way to make them work. Active components can also be used to amplify signals.

by J. C. G. Lesurf University of St Andrews Astronomy Group, Scotland.

Category Engineering - Wikibooks

This category contains a number of subcategories, books, and pages related to Electrical engineering. Books can be found on the Engineering EE. Courses can be found at Wikiversity:School of Engineering.

Subcategories include specific engineering disciplines, including Electrical Engineering, Computer Engineering, Mechanical Engineering, and Civil Engineering. Also, some books that are general to all disciplines are listed here.

Digital-to-analog converter

A DAC converts an abstract finite-precision number (usually a fixed-point binary number) into a physical quantity (e.g., a voltage or a pressure). In particular, DACs are often used to convert finite-precision time series data to a continually varying physical signal.

Digital-to-analog converter

Analog and Digital Conversion, Automatic Control Engineering, Automotive Systems. Basic Electrical Generation, Basic Electricity, Biography of Nikola Tesla.

Circuit Idea, Circuit Theory, Communication Systems, Control Systems. Digital Circuits, Digital Signal Processing, Electronics, Embedded Control Systems Design

Embedded Systems, Practical Electronics, Power Systems Analysis, Design, and Control Microprocessor Design, Engineering Tables, Semiconductors, SensorNetworks

Thursday, April 17, 2008

Science Toys - Edutainment at Home

Make toys at home with common household materials, often in only a few minutes, that demonstrate fascinating scientific principles. See also the Science Blog, - Creator - Simon Field

Science Toys - Edutainment at Home

This Website is a valuable resource for students to learn basics and get interested in electronics and computers - delabs

Science Toys - Edutainment at Home

Electromagnetism: - An electric motor in 10 minutes

The motor is simply a battery, a magnet, and a small coil of wire you make yourself. There is a secret to making it (which I will of course share with you) which is at the same time clever and delightfully simple.

Other Projects - Fun with High Voltage, A 10 minute railgun, A 30 second motor.
    Radio: A quick and simple radio

    The reason a crystal radio does not need any batteries is the amazing capabilities of the human ear. The ear is extremely sensitive to very faint sounds. The crystal radio uses only the energy of the radio waves sent by radio transmitters.

    Others are Building a radio in 10 minutes, Build a portable crystal radio, A radio out of household items, A simple AM transmitter, The Three-Penny Radio.
      Computers and Electronics: A Computer Controlled Transmitter

      In this project we will build a very simple radio transmitter that you attach to a serial port on your computer. The computer then runs a free program that converts words you type into radio signals that are decoded by another computer, using a cheap radio receiver, and a sound card.

      More - A Free Space Laser Data Transmitter, Fun With Solderless Breadboards, A Simple 1 Watt Amplifier

        Friday, April 11, 2008

        Electronics Club - John Hewes

        A website for anyone wishing to learn about electronics or build simple projects. Written for beginners but used by many others as a quick reference.

        Example Projects, Construction of Projects, Soldering Guide, Study Electronics, Electronic Components, 555 Timer and Circuit Symbols.

        Electronics Club - John Hewes

        This is good place to start your electronics study, it has a practical and simple Approach - delabs

        Electronics Club - John Hewes

        Starter kit of parts

        If you are new to electronics and would like to try adapting published projects, or designing and building your own circuits, you need to have a small stock of components available.

        Monday, April 07, 2008

        Edison and his Inventions

        Thomas Alva Edison also known as "The Wizard of Menlo Park" was an American inventor and businessman, He is known for inventions like phonograph or gramophone, the motion picture camera and the electric light bulb.

        Thomas Alva Edison

        Edison and his Inventions - Inventing Entertainment: The Early Motion Pictures and Sound Recordings of the Edison Companies

        The Thomas A. Edison Papers - The Thomas A. Edison Papers Project, a research center at Rutgers School of Arts and Sciences, is one of the most ambitious editing projects ever undertaken by an American university.

        Edison - By the time he died in 1931, Thomas Edison was one of the most famous men in the world. The holder of more patents than any other inventor in history,

        The Phonograph - On December 7, 1877 Thomas Edison demonstrated his phonograph at the New York City offices of the nation's leading technical weekly publication, Scientific American. The following report set off a stampede of reporters to Edison's laboratory to hear the amazing device.

        Edison National Historic Site - Where Modern America Was Invented - Thomas Edison’s home and laboratory are a step back in time, when machines were run by belts and pulleys and music was played on phonographs.  Where to the passerby, the buildings betray little evidence of the industries they once started.  Discover where America’s greatest inventor changed our world forever.

        Miami Museum of Science - The Atoms Family

        This resource contains educational activities about energy concepts, the power of the sun, energy conservation, energy transformation, electricity and fossil fuels being presented by famous gothic horror characters.

        Miami Museum of Science - The Atoms Family

        Electrical Safety - Static Electricity - Fruity Electricity.

        Miami Museum of Science - The Atoms Family

        Flying a kite near any kind of overhead wires is VERY DANGEROUS! The overhead wires could shock the kite, the electricity would then travel down the kite's string and shock you!

        Atoms Family - Frankenstein Lightning Lab

        Only electrical plugs should be put into electrical outlets. Never place anything else into an electrical socket, it may shock you or start a fire!

        Lamps use electricity to make light and can get very hot! If things get to close to a hot lamp they can catch on fire!

        Hair dryers and water don't mix, and can be very dangerous! Never use a hair dryer near water and never place a hair dryer in water.

        Sunday, April 06, 2008

        Three Phase Solid State Relay

        This is R-Y-B three phase 40A 440V AC Solid State Relay with 3-30 V DC Control Signal. It has Built in HeatSink and Fan. It is good for Controlling a Bank of heaters. This model could go upto 120A with SSR's in parallel for Proportional Control.

        Solid State Relays SSR.

        This is a Contacter replacement, it will switch R-Y-B phases. It is a high power SSR. In some places
        it is unwise to use an SSR, a Electromechanical Contacter will perform better. The merit of SSR is fast switching, no wear and tear. No dust humidity influence.

        Three Phase SSR

        Saturday, April 05, 2008

        Tacho Counter for Speed and Quantity Measurement

        This was a Custom Built Product for Converting a 10-100 V Signal from a Motor Tacho to pulses, to indicate the distance moved by Conveyor belt with Job Material. The Digital Indicator would indicate the speed and the Mechanical Counter would Log Quantity of Materials Moved.

        Process Control Instrumentation

        Tacho Counter

        The voltage was first brought down to low levels with an attenuator and zener protection. A VCO and a monostable created a train of pulses. These pulses drive a darlington transistor pair which operates the Electromechanical Counter that has a Solenoid. The voltage is also scaled, calibrated and displayed on a Digital Voltmeter.

        The circuits are partially shown here, two versions.

        Voltage to Frequency Converter ICL8038

        In this the VCO chip is 8038, it is hard to procure, but it is an excellent chip.

        VCO - Voltage Controlled Oscillator using Opamps

        This is using opamps, hard to configure and build, but a proven design.

        The VCO can also be built by a Microcontroller chip which has an analog input. Any I/O port can be the Oscillator output. This is easily possible as this system is within the 1 MHz range.

        Analog Blind Dial On Delay Timer

        It is called analog dial timer as it has no digital display, but the chip is digital it is CD4541. It is Mains operated, you could make on-delay or off-delay. By changing the caps and resistors or with even dip-switches you could get timing of few seconds to many hours. Circuit is Analog Timer 4541 .

        Analog Blind Dial On Delay Timer

        Some timers energize the relay after a set delay on power start. Some start with relay energized and turn off after set time. Motors and big systems cannot take fast turn-on and turn-off, Some systems will require sections or modules to start one after another as they are interdependent. So Timers in automation were made to effect such delays, the early ones were mechanical clockwork.

        Analog Timer

        The CD4541BC Programmable Timer is designed with a 16-stage binary counter, an integrated oscillator for use with an external capacitor and two resistors, output control logic, and a special power-on reset circuit. The special features of the power-on reset circuit are first, no additional static power consumption and second, the part functions across the full voltage range (3V¨C15V) whether power-on reset is enabled or disabled.
        • Available division ratios 28, 210, 213, or 216.
        • Increments on positive edge clock transitions.
        • Built-in low power RC oscillator.
        • Oscillator frequency range . DC to 100 kHz.
        • Power on Auto reset initializes all counters.


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