Drive a LED with a Constant Current

Constant Current Source LED Drive

This is a Constant Current Source LED Driver, When the LED driver Upper-NPN is driven by a voltage thru 4.7K the LED lights up. Assume that the Lower-NPN at bottom is absent. The current via LED and NPN is limited by R. 20mA may be ok 15mA even better. Or LED blows even transistor goes.

BC547 is like 100mA-40V-200b, Limit collector current to 60mA, use it at less than 25V and depending on the individual transistor you may get a DC current amplification of 200 times. That is 1uA of base-emitter current could give a whooping 200uA of collector-emitter current.

Still Thinking we do not have the Lower-NPN we calculate the resistor. Vcc - ( 2 LEDs * 1.7) - Vce = Vr that is the voltage across the resistor. You know ohms law and the current needs to be 15mA for a bright and long lasting LED. Lastly 1.7 the forward drop of a green LED and 0.6 a saturated or Turrned-On NPN Vce.

Now you use the Lower-NPN, The above calculations do not hold anymore. Let us think a small current is flowing in the LED. Then the voltage across R is less than 0.7V, that means base-emitter diode of the Lower-NPN will not get to conduct. The Collector does not draw any current away. Now think that more current flows in LED, the voltage across R builds up above 0.7V the Lower-NPN is biased. The collector of Lower-NPN starts drinking current from the base of the Upper-NPN. So The Upper-NPN starts losing its bias. This lowers the LED current and contains, regulates or controls the LED current as shown in the formula.

BC847/BC547 series; 45 V, 100 mA NPN general-purpose transistors
LEDMUSEUM.ORG-THE LED MUSEUM-Reviews of LEDs

FET Current Source

This is a constant current source using a FET. This is the most simple replacement to series resistor to limit current. The N-Channel FET BF256C can give 15mA current.

• A current source based on a JFET
• 4QD-TEC: Current sources and mirrors
• Current source - Wikipedia, the free encyclopedia
• Field effect transistor - Wikipedia, the free encyclopedia

More at - Schematics of delabs: LED-Circuits

LM555 Voltage Doubler and More 555

This circuit shows the voltage doubler working with a 555. LM555 has good drive 200mA, both Vcc and Gnd.

My 555 Circuits here - Schematics of delabs: 555-Circuits

Ni-Cd and Li-ion Battery charger Generic

This is a Generic charger that is made by many brands, the circuit is an approximation of all. Some improvements suggested. Some brands in europe and usa also use this circuit. This works well, but may not be in the best interest of battery life. The cost of the charger needs to be low. So this design or configuration is popular.

Battery Level Indicator 

The more care you show in the charger's battery charging and discharging; the longer its life. Today i manage my UPS batteries manually, both charge and discharge. The batteries are expensive, there is no better way, that is affordable.

Switching Battery Charger with L296 - del20031

Take batteries seriously - this is the source of transportation, power, solar energy reservoir etc. More so in the Future - start here Battery University.

Analog Op-Amp Tutors with Gadgets

I have made some iGoogle Gadgets with canvas view, these are analog opamp tutors. Interactive Tutorial with Simulated Meters and Potentiometers, demonstrating how Operational Amplifier functions in different configurations.

Interactive Tutorials using Virtual Electronic Components 

Slide the Potentiometers just like you would operate a Sliding Control. Drag the Knob on Pot to increase or decrease the resistance. The Resistance is shown is blue letters and dynamically alters value as you slide the pot.

The mV Source is varied by just moving mouse pointer over the two buttons, no clicking. This reduces finger strain and also you have a long lasting mouse. The mV buttons are special, the variation picks up speed if you let the mouse pointer remain on the button. This is Ramp-up and Ramp-down. This enables you to set it faster with just two buttons.

Finally you have a DVM a Digital Volt Meter that just Displays the Voltage at any Point, this readout value has to be noted down.

Op-Amp Simulation using Javascript

From Soldermans Basic Electronics

• Inverting Amplifier Gadget
• Non-Inverting Opamp Gadget
• Buffer Unity Gain Amp
• Dual Differential Amp
• Differential Amplifier
• Instrumentation Amp

If you wish to examine the code - Analog Tutorials Project Page

Introducing a new delabs icon - Elektrick the Power Jedi

I am also attempting a Toy Scope or a waveform display.

Mains Voltage Stabilizer Circuits

Mains Voltage Stabilizer Circuits

These circuits were drawn for a person in Africa. See the thread here… stabilizer circuit. They were not tested by me, but are quite close to a practical design.

Stabilizer Step up 230V AC 500VA

This circuit is a design i did, not tested by me as yet. It can Stabilize Mains voltage to around +/- 10% . It can be used for both 110V AC or 220V AC inputs with modifications. The Output is 220V AC. There is an overload, under voltage and over voltage trip circuit. With some tweaks and modifications it might work.

Solid-State Stabilizer Step up 110V AC

This circuit is a design concept, not tested by me and i did it just to explain some ideas. The circuit uses opto-coupler MOC3041 of Motorola and the Triac BTA-16-600 of ST as a solid state switch or relay. It also uses the LM324 quad opamp from National Semiconductor which is low power and single supply. As the MOC3041 switches the Triac at zero crossover there is no inter-winding short of transformer on crossover hopefully, the control circuit is designed in such a way that more than one triac will not be turned on at a time, i would like you to give feedback.

EEVblog – Electronics Engineering Video Blog

Off-the-cuff video blog and Podcast of interest to anyone involved in electronics design. Electronics professionals, hobbyists, hackers, and makers will find something of interest here.

EEVblog - Electronics Engineering Video Blog
David L. Jones is an electronics design engineer based in Sydney Australia. He has over 20 years experience in the electronics design industry.
If you are into electronics, computers, or anything else remotely technical, then I'm sure there will be something of interest for you here. There are various electronic projects,
TRONNORT Technology - Electronics Resourse Site

Perpandle has been UpGraded Again

The Center piece is a bamboo tube. The bottom of this pipe is a brass part. A autotransformer dial is the big washer. The LED array is from a Failed China Lamp and The Enclosure is a 10 CD Box. The Top Byzantine Structure is a Pepper Cap from Africa and a Furniture Knob.

Perpetual Candle - White LED Lamp on Ni-Cd

From Hobby Hound - DIY Electronics

Read Earlier Post - Perpandle Design

Radio Electronics Projects - Hans Summers G0UPL

"I am not a professional electronics engineer, nor do I have an electronics degree. I make no claims for technical accuracy, good design, or necessarily even originality for the contents of these pages.

Rather, I am a simple enthusiast attempting to convey my love and enjoyment of radio, electronics, laptops and computing and perhaps to inspire YOU to build something too."
Radio Electronics Projects - Hans Summers G0UPL
This ultra-low power QRSS beacon was designed to be as efficient as possible, and produce a milliwatt or few from low voltage, low current supply. My intention was to investigate the use of natural power sources to operate the beacon.
Steve G0XAR visited the G0UPL shack and took some photos of proceedings. Combined with a sneakily obtained photo of G0UPL sleeping somewhere in Texas en-route to Ozarkcon 2007, G0XAR produced this very nice QSL card suggestion!
Low power QRSS beacon - Hans Summers G0UPL

BEAM Robotics - Simple Nature Inspired Bots

BEAM is an acronym standing for Biology, Electronics, Aesthetics, Mechanics. While BEAM robots are often simple (consisting of a solar cell , motor, 2 transistors , and capacitor ), robots as complicated as 8-jointed, 4-legged walking spiders have been built using the principles of BEAM.

Solarbotics.net - BEAM Reference Library

The BEAMAnt is a phototactic bot which has potentially complex behavior depending on the light level. It has two photodiodes for light sensing, and two antennae which switch the motors into reverse when they touch something.



Mechanisms and principles

The basic BEAM principles focus on a stimulus-response based ability within a machine. The underlying mechanism was invented by Mark W. Tilden where the circuit (or a Nv net of Nv neurons) is used to simulate biological neuron behaviours. Some similar research was previously done by Ed Rietman in 'Experiments In Artificial Neural Networks'. Tilden's circuit is often compared to a shift register, but with several important features making it a useful circuit in a mobile robot.

BEAM Robotics - Wikipedia

Solarbotics offers robot kits, solar-powered robots, books, electronic components, motors, parts and information on the expanding field of BEAM Robotics.

TomboT - and the home of Liverpool Universities BEAM robotics

"Myself and some friends demonstrated to the University how simple robots can be built which provide an excellent learning platform, and as a result the University have changed the way they utilise their Year 1 lab sessions to include our robots". - Tom Elner

One more nice site BEAM Robots and also BEAM Online.

Renewable Energy -Solar Electronics

Wide range of up to date information about alternative energy generation. Our main focus is on wind power and solar power for the home, but you will also find details on topics as varied as electronics and biodiesel recipes.

Renewable Energy -Solar Electronics


Make a simple solar charger for 4 AA rechargeable batteries. In this article you will find out how to make a very simple solar battery charger for 4 AA rechargeable batteries using a small 6 Volt solar panel. A labelled photograph of the completed charger is provided at the end of the article.

Basic 4 AA Solar Battery Charger Plans

My Notes-

Here are very useful ideas on solar energy and frugal lighting techniques. Solar Energy goes with Frugal Designs and things like UPS Uninterrupted Power Supply and High Efficiency Circuits. Green and Small Carbon Footprint all finally means how Energy Efficient is our Lifestyle and Preserving the Planet the way we found it, without leaving any scars.

LED Lamp – Simple Bed-Lamp Circuit

LED Night lamp, Clock Lamp to see time at night. It is a Green Lamp just 50mA, but its Blue in Color.



This can be a first LED Lighting project anybody can do. Just twist wire, use insulation tape. Get a Nice Mains adapter that will provide 6V DC. 5V also will do. A prior Knowledge of Ohm's law is essential.

LED Flashlight made out of a China Lamp

LED Flashlight made out of a China Lamp that was busted on a High voltage surge during a Thunderstorm.

I got many LED lamps, mainly from china. The Chinese Entrepreneurs are Creative and Adventurous. There is a problem though, the quality, reliability and safety factors are not so good. These are so for even branded china products. That is offset by a affordable price.

Then China is going thru the learning curve like Korea and Tawian. Now Taiwan makes world class products.

Professor Mark Csele - Projects and Hobbies

"I present, below, a collection of projects I have worked-on over the past few years. For over a decade, I had taught both embedded systems (microcontroller technology) and digital signal processing and practice what I preach...."

Professor Mark Csele - Projects and Hobbies

Nixie Thermostat - A heating and cooling thermostat employing technologies spanning fourty years from the unique Nixie tube display, circa 1960's, to a PIC 18F microcontroller, circa 2006.

A High-Powered Power Backup Inverter - The working prototype of the 2 KVA inverter is complete. Fed from an array of lead-acid cells totalling 600 Ah (at 12 Volts), it easily drives real-world loads such as single-phase motors. The inverter has been tested and found to operate at an efficiency of between 71% and 82% driving a variety of both inductive and resistive loads

LED Lamp or Bulb with Flashlight option

This is another LED lamp from China, these people make nice lamps and also good designs of the plastic enclosure. Here by a clever enclosure design it is both a emergency mains bulb and Torch/Flashlight.

The price is low and they use a small sealed lead-acid battery worth 4.5 V and around 1 AHr. That means it could give an hour of performance at 1 A drain/usage. The voltage by the elapsed hour could be near 4. Here the battery failed, vibration or leakage; OR combination of both. The acid, very little or even corrosive vapor has eaten the copper wire of positive wire/junction. The Cut Red wire, broke circuit equilibrium and burnt the R? = 3.3K - 4.7k ?. The lamp failed all other parts intact.

How it works ?

It uses a step-down cap, this is very tricky. It has to be a HV cap overrated and excellent quality. These caps not good enough. I am partially responsible for this cap idea spreading around. It was decades ago in relation to bringing down the cost of industrial. automation timers. The transformer had to go and smps solution too much; a resistor inefficient. I was triggered by the choke used in tubelights to bring down voltage after firing. So if L can be used, then even C for low currents, no heat wasted. The timer worked, successful sales. Idea/Concept became popular. This idea also misused by others to save cost. This design needs an Axial Polycarbonate/Polypropylene 630V/1KV cap for reliable operation.

Now this 18 LED array, has no current limit, is it not quite a problem. The chinese are innovative on saving cost, here its fine, but.many times we can sacrifice quality. In this design the LEDs drop around 3.3V and the Transistor 1 Volt as it is not driven to saturation. On full load the battery also deregulates, so it does manage to save itself. This transistor also serves as a mains detector along with the 1N4148. On mains failure the LED lamp turns on Automatically.

Another Lamp had a Burst out 100uF cap this means, surges or spikes are damaging the 1uF 400V Plastic cap used for current limit.

Recommendations to such Lamp Designers

Use Metalized Polypropylene MPP - rated for 440V AC continuous working. That means it must be rated like a Power Factor correction/saving capacitor. It may mean 1KV DC operation.

• Use an Axial 1uF polypropylene 630V DC or 440V AC Capacitor
• Sell it with a Marketing Advantage as Power Factor Compensation.
• Use two 2.2uF 630V DC Axial MPP, one on Live and the other on Neutral.

A house using Motors and Fans will have inductive elements, even tubelights that have chokes 50/60 Hz kind. This is compensated by capacitive loads. So each of these Capacitor LED lamps can be a Green Lighting and PF compensator.

Perpetual Candle - White LED Lamp on Ni-Cd

This is a easy to build LED lamp circuit for Learning and building skills. This is the first draft schematic V 1.0. It will need improvements for Higher Power Lighting.

From Schematics of delabs

I will give a short summary, The LM317 here configured for around 6.4V DC. The Q3 BC547 limits the current, you can select R3 to suit, make it 1/2W. The Ni-Cd battery pack 1.2 * 4 will not get Over-Current or Over-Voltage due to this circuit.

The IRF540 Mosfet or any other equivalent you have around, along with Q2 BC547 forms a current source for the parallel 12 LED array. Ultra-bright White LED at 20mA each or use a 1W ready LED Chip. R4/R6 can be selected for the Max LED current. The voltage of LED is around 3.1 and 20mA * 12 = 240mA is the max current. You can Tweak the design for even 5A or more but then you will need a DC/DC High frequency converter in place of LM317. The Current source also needs to switch to improve efficiency. A PWM on the mosfet gives brightness control. The entire solution (switching) can be found in many chips with semiconductor vendors today.

From Hobby Hound - DIY Electronics

One Single High Current LED may work well. 12 Matched LEDs also can be used. In LED Array some are dim, put min. resistor (3.9 ohm) for all 12 for current sharing. The resistor addition will impar the ability of Candle to work at lower battery voltages. Also resistor is less green, It wastes power, so use PWM and Single Die high current LED. Ni-Cd system may last over 5 Years if Candle is allways on Mains. Sealed Lead Acid system may go upto 2-3 years life but will have more punch. A SuperCap system may last more than 12 Years, i feel.

Source in Cadsoft Eagle format - candle.zip

Proto-PIC - Prototyping for Hobbyists

eShop and How-To Videos for anyone who has an interest in Microcontroller Programming & Development. Components and Kits for the Electronics Enthusiast.

Proto-PIC - Prototyping for Hobbyists

A site designed for electronics and prototyping hobbyists and enthusiasts. This site has grown and is now a useful knowledge base and online shop for anyone who has an interest in Microcontroller Programming & Development or for anyone who has a love of electronics.



BBC Microbit - Accessories, Board & Kits for the Micro Bit

The BBC micro:bit is a tiny little computer, that is easy to program and small enough to fit in your pocket. It has built in Bluetooth , motion detection, a  compass,  and an LED display.  We manufacture our own range of micro:bit Accessories and Kits right here in sunny Scotland.

RelChron Limited
Unit 17, Kirkcaldy Enterprise Centre, Myregormie Place, Mitchelston Industrial Estate
Kirkcaldy, Fife, Scotland, KY1 3PF

Fritzing is Product Design or EDA in Simplicity

"Fritzing is an EDA - Electronic Design Automation software with a low entry barrier, suited for the needs of designers and artists. It uses the metaphor of the breadboard.."

Fritzing is Product Design or EDA in Simplicity

"in the spirit of Processing and Arduino, developing a tool that allows users to document their Arduino and other electronic-based prototypes, and to create a PCB layout for manufacturing."

Fritzing Starter Kit to start learning Arduino



Related Reading -

• Processing - open source programming language and environment
• Arduino - open-source electronics prototyping platform.

Sparkle Labs Electronics DIY Kits

Sparkle Labs brings their expertise in design, branding, usability, and education to create hi-tech, hi-touch products and environments.

Sparkle Labs Electronics DIY Kits

Like the old Radio Shack spring circuits but updated with modern teaching styles. The growing DIY movement is empowering people to take control of their products and environment.



Discover Electronics Kit contains everything you need to learn the basics of electronics and make your own projects. It contains the most common electronics components as well as a prototyping breadboard for you to get started right away. Easy full color diagrams teach you how to bring your own ideas to life.

Pololu - Electronic Modules for Robotics

Small electronics modules and simple mechanical components for for robot and motion control. Web Store provides parts like small gearboxes, breadboards, servos, and robot kits too.

Pololu - Electronic Modules for Robotics

The Orangutan SVP robot controller is a complete control solution for small and medium-sized robots running at 6 - 13.5 V. The module is designed around the powerful Atmel ATmega324PA AVR microcontroller (32 KB flash, 2 KB RAM, and 1 KB EEPROM) or ATmega1284P (128 KB flash, 16 KB RAM, and 4 KB EEPROM) running at 20 MHz .



Orangutan SVP-1284 Robot Controller

The Orangutan SVP is also available as an SVP-324 partial kit or SVP-1284 partial kit that has all of the surface-mount parts pre-soldered and a variety of through-hole parts included separately.Mechanical Components include Motors, Gearboxes, RC Servos, Wheels, Tracks, Ball Casters etc.

ARobot Projects and Experiments

ARobot's controller board accepts the Basic Stamp II (purchased separately) which controls motors, LED's, buzzer, and other devices.

ARobot Projects and Experiments

• Rugged aluminum frame (no plastic or wood)
• Dual front whisker sensors
• Rear wheel steering servo motor
• Front wheel DC gear drive motor
• Optical wheel encoder for distance measurement
• On-board coprocessor handles all motor control

ARobot's controller board has the ability to control 3 additional RC (Remote Control) servo motors which are commonly available at hobby stores for less than $20 each. These motors can be used to create a small robot arm or a moving head. The body contains openings to mount 2 of these RC servo motors.
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Arrick Robotics

Arrick Robotics was founded by Roger Arrick in 1987 after the personal computer accessory market became dominated by the far east which stunted the growth of Arrick Computer Products - a maker of switch boxes and power control products since 1980.

AVR Circuits by Vassilis Serasidis – AVRsite

Circuits based on AVR microcontrollers (?C) from Atmel. "little powerful things"

AVR Circuits by Vassilis Serasidis - AVRsite

A mega32 based low speed oscilloscope. It can be used to measure signals up to 5 kHz. The input voltage range can be up to 24V AC or 30V DC. Designed by: Vassilis Serasidis - Language: C ( AVRstudio4 + WinAVR )

AVR based oscilloscope

RobotShop Distributon - Automate your Existence

Specialized in personal and professional robot technology and offer a wide range of robotic products.

RobotShop Distribution - Automate your Existence

Supplier of Real robots, robot toys, robot kits and robot parts for building your own robots. Also robots that help out in House/Office Maintenance.



GEARS-IDS Extensive Invention and Design System

• Build and control your own custom robots
• Heavy duty parts made of steel and aluminium
• No programming or soldering required
• Standard hole spacing and modular design

The GEARS-IDS Invention and Design System gives teachers all the necessary tools to help students create world class engineering and robotics challenges in the comfort and convenience of their own classrooms in one complete package. From Trebuchets to Autonomous Robots,
Education Concepts:

• Apply math and physics concepts to solve challenging problems
• Exposure to engineering, mechanisms and machines.
• Fundamentals of mechanics, electronics and pneumatics

Mains Adapter 230V AC 50 Hz to Rectified DC

Mains Adapter Converts 230V AC 50 Hz to Rectified DC which replaces a Battery Pack. It was also called Battery Eliminator by older generations as it was used to save Battery Cost in AM Radios.

Mains Voltage and Power Circuits

The most important product safety aspect is the transformer, may it be well isolated, may it use a split bobbin, may it have a visible insulation between primary and secondary. May the thin primary wires not slip into the secondary .. when not using split core. Use a Layer to layer insulation for better safety. Use a nice laminated thin sheet alloy core stack, then no hum and no heat. vacuum impregnate magnetics. May the customer be safe and sound.

Power Electronics & Solar Energy

Remember only if we keep a customer alive, he will buy more products. From medicines to transport, from bread to gadgets. The customer is the most valuable asset. If he is kept Alive and Healthy and in a Cheerful mood … He will Buy !!

Torch or Flashlight Circuit Improvements

I fixed a China Torch with New LEDs and a Diode, it failed probably on a drop shock, the battery wire cut … then when put on charge Few LEDs went bad, as battery was absent in ckt.

The Success of the LED Lamp

design review - 1.5uF voltage rating can increase like 440V AC. A current source with low dropout voltage would be great but it builds the cost. The wiring has to be robust. A diode added to keep LED current within some limits on battery overcharge.

LED Lighting - The Future is Here

These type of Torches and Lanterns should not be Turned on when charging. This may blow the LED Array. As long as the LEDs have a constant current flowing through them they are safe. It could be anywhere between 10mA to nearly 25mA depending on the type. LED Arrays can be in parallel or series or a combination of both. The datasheet has to be studied for the high current types.

Never subject these LEDs to a Reverse Bias voltage that is very high. It means reverse polarity. Never allow the current to go so high that it overheats the device, reduces longevity or even damages instantly at high current. These devices survive short pulses of high current. Hence PWM is a way to protect devices and arrays too.

Emergency Light with Fluorescent Tubes

Emergency Light for Portable Use. Note Charger and Battery not Shown. Design from Ludens
12 Volt fluorescent lamp drivers: Three schematics of 12 V drivers for 2, 8 and 20 Watt, plus a lot of explanations about fluorescent tubes. Use the drivers for camping, emergency, boating, etc.

Improper Design of Magnetics or Testing at low voltages can damage the switching NPN. The NPN must have fast switching time, see towers for Cob in pF and .fT in MHz. This may Oscillate for 100 kHz so it has to switch fast, then less heating and better beta at high freq. Choose such a NPN.
The Ic or max current of the NPN can be few times above the current consumption you have planned with the gadget. As a thumb rule if this is a 10W at 10V that means 1 Amp current. Hence choose a device 5 times above 1 A. Use a 5 A device or a 7 A for reliability.

The voltage selection of NPN must also take into account the transients in the switching. If its a sine oscillator like above, the transients, spikes are mild but in square wave switching, the spikes can be very sharp on resonance. These low energy zaps can weaken the NPN and deteriorate its switching and cause heating and eventual failure. So many CFL lamps and Emergency Light's fail quickly as they are not built robustly.

Even this circuit above is good only if is built very carefully.

Mains Powered China Emergency Bulb

A typical Mains Powered China Lamp. On power down, LED light turns on for around 1/2 hr. Gets damaged on lightning activity and wide (uS not nS) transients above 300V. Drawing may have error.

Many products and components were made over the last 10 years with less regard to voltage and current ratings and product safety.

The circuit design is not everything, engineering the product for reliability, usability and safety is very important. This Schoodle is like a Satire to emphasize the responsibility of electronic manufacturing and engineering.

Two PCB Mills - Jonathan Ward and Ilan Moyer

Make your own PCB Mechanical Routing/Erosion/Milling Machine at a low cost.

PCB Mill - Jonathan Ward - MIT

"Design a low cost circuit board milling machine optimized to be mass-produced."

Low Cost PCB Mill lan Moyer

The overall device has a working area of 4" x 6" with a footprint roughly the size of a letter-sized sheet of paper. Capstan drives were chosen for their simplicity and low cost, and also serve as torque limiters to prevent excessive loads on the small-diameter drive cables.

Nomadic Research Labs and Steve Roberts

The story and evolution from Behemoth to Microship, water-type HPVs. microship.com. Technomadic goodness.

Nomadic Research Labs and Steve Roberts

Online Store for Technomadics

Surplus Kayaking Books Parts Sensors Nautical Controllers GPS Trackers Geek-free Zone marine electronics.

Powered USB Hub Help PC Interface

I got a strange problem as i added more and more peripherals, the pc gave odd messages, "i cannot detect what you are doing" and things like that. I almost flipped trying to locate the culprit. The problem was not in any peripheral but in the USB port powering the system itself. The SMPS was not loading much. Certainly the peripherals were drawing more and the warning could have been more like "use your own power".  Computer Data Interface

I could not locate a powered USB with any vendor close by, so i built one and it works perfectly, Now it doubles up as a UPS Low Batter Indicator, by rare coincidence. If the Unregulated DC is above 7 volts, then no bugs. When i adjust the unregulated DC to the 7805 to around 6.9V, then i have a advance warning system.

Wireless USB - Wireless Extension to USB

When power fails, i keep working and listening to music from a Flash Thumb drive. When music stops, i turn of computer, the lead acid batteries gone below 20 V DC. This avoids deep discharge of my batteries. The Powered USB gets undetected when the supply falls below 4.5 probably.

Bug Labs - Modular Stackable Embedded Computer

Bug Labs - Modular Stackable Embedded Computer

BUGbase is a fully programmable computer, with a CPU, RAM, rechargeable lithium-ion battery, USB, Ethernet, micro-SD and serial interfaces, and a small LCD with button controls.

BUGbee is a low-power radio module based on the 802.15.4 protocol, perfect for creating a personal area network (PAN) for machine-to-machine (M2M), home automation and intelligent grid applications.

BUGvonHippel is a breakout module to which you can connect sensors, wires, and USB devices. This module is named after Dr. Eric von Hippel of MIT who wrote the book Democratizing Innovation.

Recording Technology History

1877 - Edison made the first recording of a human voice ("Mary had a little lamb") on the first tinfoil cylinder phonograph Dec. 6 (the word "Halloo" may have been recorded in July on an early paper model derived from his 1876 telegraph repeater) and filed for an American patent

Dec. 24. John Kruesi built this first practical machine Dec. 1-6 from a sketch given to him by Edison that was made Nov. 29 (not on "Aug. 12" that Edison mistakenly wrote on another sketch in 1917).

Recording Technology History



When Kruesi heard Edison's first words Dec. 6, he exclaimed "Gott in Himmel!" (but these words for "God in Heaven" were not recorded and thus have been forgotten). Others before Edison had tried to record sound, but Edison and his tinfoil phonograph were the first to succeed.

History of sound recording

The phonograph expanded on the principles of the phonautograph. Perfected by Thomas Edison in 1878, the phonograph was a device with a cylinder covered with an impressionable material such as tin foil, lead, or wax on which a stylus etched grooves.

One Watt Mains LED Lamp or Tubelight

Lots if Light on One Watt, yes this works, but should be built by those experienced in High Voltage usage and Knowledge of insulation techniques.

This has to be encapsulated in a insulated fire retardant plastic enclosure. You can change the values around what is indicated to experiment with types of White LED available.

This project is not for Youngsters or those who are still learning. High Voltage can cause injury and can be fatal too, when used or applied without experience, training or supervision.

Charger for Portable Devices like iPod

This is a simple charger you can build for devices like iPod or iPhone. It works for ipod touch. It can be modified for any device. This may need no modification for devices that are charged using PC USB port.

Power Electronic Circuits

This is a Schematic Doodle called Schoodle. Use it for Learning and understanding. Build and test only when you have practiced and gone beyond simple electrical and electronic circuits. Mistakes can damage your portable device or even waste your components. Hence take care, work systematically, not like me. See the mess i have created below.

Controlling The Real World With Computers

This site uses hands-on experiments to show the basics of how real things in the real world are controlled with computers.

Controlling The Real World With Computers

This site is also for anyone who is the least bit curious about monitoring and controlling such things as motors, lights and switches, or recording and playing everything from sound to the arm position on a robot.

Experiment 7 - Bi-directional Control Of Motors And The H-Bridge

It would be useful to be able to run a motor in either direction. That's simple with a motor of the type that's been used in the experiments thus far. Reverse the DC power connections on such a motor and its shaft will rotate in the opposite direction. One way to control direction is to use switches arranged in the following manner:

Joe Reeder

VeeCAD for Stripboard with Auto Router

VeeCAD takes a schematic generated netlist and assists you to build a layout - but on stripboard (Veroboard). The usual design tools are provided: netlist import, component footprint definition, component positioning, wiring and connectivity check.

VeeCAD for Stripboard with Auto Router

Engineers and hobbyists use VeeCAD for prototypes and small quantity builds, saving hours planning layouts on graph paper.

Transistorized from - PBS Online - Tutor

Transistorized from - PBS Online - Tutor

Lesson 2: Scientists at Work
Students select an electronic invention and research who and what contributed to it.

Lesson 4: Using Transistors
Students build circuits to see how transistors function as switches or amplifiers

Peek at some of Brattain and Schockley's Lab Notes

Electricity and Magnetism - Molecular Expressions

These Tutors which are Interactive as well are useful for Students and Enthusiasts to enhance the Text Book reading.

Electricity and Magnetism - Molecular Expressions

These pages are good for any person who want to be more familiar with magnetism and electricity. This probably means everyone. Today Electricity Basics is General Knowledge and also an Absolute Essential.

Interactive Java Tutorials - Covers principles, physics, and devices used in electricity and magnetism.

TechLib - Electronic Experimenter Records

TechLib - Electronic Experimenter Records

A technical library for the hobbyist and experimenter. - Charles Wenzel

• World's Smallest Geiger Counter
• Karen's Mic. Input Telemetry Device
• Temperature Controlled Ovens
• Two-Transistor Atomic Frequency Standard
• Super-Sensitive Ionization Chamber
• Cockcroft-Walton Diode Voltage Multipliers

Science Fair Ideas

This will be a collection of unusual ideas for somewhat difficult science fair projects - hopefully not a repeat of other sources.

Makerbot - 3D Mechanical Prototype Synthesis

The basic setup you'll need to build a plastic extruding CupCake CNC machine. from Bre Pettis
Makerbot - 3D Mechanical Prototype Synthesis

Makerbot is an open source robot that helps people make robots that make things.



"The only fear is that it can Replicate itself" -   ....When i had posted first..

MakerBot Industries is a Brooklyn, New York-based company founded in January 2009 by Bre Pettis, Adam Mayer, and Zach "Hoeken" Smith producing 3D printers. MakerBot builds on the early progress of the RepRap Project. - 2013 updated

Complete Pro 3 axis CNC kit

Kit 601: Complete Professional 3 axis CNC kit: Complete kit for Hobby application, use this kit to gain time on your hobby transformations or DIY milling machines

Complete Pro 3 axis CNC kit



Badog Switzerland

They manufacture a high-tech precision, rigid CNC mill/engraver for the price of a CNC engraver.

Updated - Oct 2013

Audio Consulting Switzerland

Audio Consulting Switzerland

Specialists in very high quality audio, Designs Amplifiers, Preamplifier, Phono Preamplifier and R-evolution Turntable etc.

Adapting New Technologies into Classic Hi-Fi systems, without compromising on Decades of Audio tradition.

MITA The Mains Independant Tube Amplifier
SE battery tube amplifier

Features

Stereo SE 15w / Channel, Three Silver Rock transformers per channel, Fully Lithium battery powered, All silver internal wiring, Veneer to customer's request.

Audio Hi-Fi DIY – Claudio Bonavolta

"Do-It-Yourself … That's the choice I did and the reason you'll find several schematics, mainly for tube electronics, but also some formulas for loudspeakers"

Audio Hi-Fi DIY - Claudio Bonavolta

Measures Conversion, Electronics, Loudspeakers, RIAA preamps, Solid state MC preamps, Solid state preamps and Solid state amps.

(Proper Loudspeaker Design is more complex than Launching Rockets into the Ocean )

Tapered Quarter Wave TubeFirst described by Paul Voigt in 1930, TQWTs allow a good quality-to-price ratio. They are also easy to build.Similar to transmission lines, the TQWT is different by its shape, a kind of horn is used as back load but the driver is not placed at the beginning of the cone as usual but on its side.

In closed boxes, the back wave of the speaker should be completely absorbed (= converted in heat) by the damping material.As the speaker is nearly transparent to sonic waves, if a back wave returns after a reflection on the back wall, some part will also come out through the speaker with some delay giving a not very clean sound.

Electronic Projects - Rickard Gunée

Electronic Projects - Rickard Gunée


PIC Game system - Hardware description of the system that is running pong and tetris.

AVR Color Clock - A clock using the standard resistor colors (+2) to show time with two RGB LEDs.

PIC Mini Dice is an electronic dice based on a PIC10F200 and built with surface mounted components.

Even though this is a very simple project, it requires some surface mount soldering skills, proper tools, and a steady hand as it is built with surface mounted components only.

Mike Ellis - Electronic Projects Tutorials

The Multimedia Electronic Literature & Learning Internet Site A website dedicated to the advancement of electronic engineering skills by Mike Ellis.

Mike Ellis - Electronic Projects Tutorials



Complete schematics and code for a 68HC11 based frequency counter, square wave synthesizer, sine wave synthesizer, programmable filter, capacitance and inductance meter, with a digitalker speech synthesizer output.

• 68HC11 Function Generator
• Oscilloscope Block Diagram and Schematics
• Dual 0-15 Volt Tracking Power Supply
• Audio Amplifier
• On-Line Tutorials

High Speed Photography - HSP

Here is a small list of photography related circuit and projects including High Speed Photography or HSP that uses Electronic Circuits to operate the Trigger or Lens Shutter.

High Speed Photography

"Many physical processes evolve on timescales shorter than the human eye can resolve. Effectively, this means the details of how the process changes with time are lost in a blur. High speed photography, or HSP, is simply photography with extremely short exposure times,....



....All control systems can be classified into one of two broad types - Open Loop and Closed Loop. The difference between them is the use of feedback via input signal. For the DIY high speed photographer, the difference equates to reliability, expense and simple electronics. "

Lightning Activated Camera Shutter Trigger

This circuit is used to trigger a camera's electronic shutter circuit when a flash of lightning is present. This circuit would also work for photographing fireworks displays or other events involving flashes of light.

Darkroom Camera Shutter Timer

This circuit was designed to control a film exposure shutter for a darkroom. It has 8 time steps ranging from 0.35 seconds to 4 seconds

Motorized Video Camera Mount

This article describes a motorized, waterproof mount for a miniature video camera. If a suitable waterproof camera is used, this unit can be used outdoors.

PIC RISC microcontrollers - Peter Luethi

This website provides you helpful information about Microchip PIC 8 Bit RISC microcontrollers. Several assembler source code listings are available for non-commercial use.

PIC RISC microcontrollers - Peter Luethi

There are also tools for using your PC for measuring or regulating electronic applications. I'am working on several projects, e.g. a precision digital altimeter to use in my radio controlled airplanes.



Radio Controlled Modeling - RC Circuits

PIC Assembler Projects, PIC Assembler Modules, Electronic Circuits, Student Projects, R/C Modeling Circuits, Servo Checker. Projects of Peter Luethi - Switzerland.

Precision Digital Altimeter



The current concept incorporates a wireless transmitter and receiver and is thought to be used for remote controlled airplanes or appliances with two seperate parts. In other words, we have one dedicated transmitter (acquisition, filtering) and one dedicated receiver part (user-interface, look-up table, calibration, storage),....

Vacuum Tube-G Pages from Peter

Some Audio and other Articles/Projects on Vacuum Tubes or Valves. Also he has made Online Calculators .. Bias Tool, Gain Tool and Low crossover cap.

Vacuum Tube-G Pages from Peter
Some articles written by Alan Kimmel, as it did in the years 1993 to 2004 on the original Tube Labs.

• The Choke Assisted Mu Stage
• Why use the Kimmel mu stage
• 7 A few variations of the mu-stage

Related -

TubeLab - Dedicated to advancing the state of the art in affordable high end audio.

Kits Surplus Parts - Electronic Goldmine

Stocks millions of unique and hard to find electronic parts, kits, motors, switches, Largest selections of low cost, high quality kits.

Ginormous Surprise Box

Kits Surplus Parts - Electronic Goldmine

Visit - The Electronic Goldmine Map

Interface - Electronic Goldmine Tweeter

The Electronic Goldmine, 9322 N. 94th Way, Suite 104, Scottsdale, AZ 85258 - USA

Electronics Parts for Hobby - BGMicro

Electronic Parts, Electronic Kits, Hobby Electronics, Educational Electronics, Surplus Electronics.


Electronics Parts for Hobby - BGMicro

They also have a "BGMicro Virtual Sidewalk Sale"  Here you will find items that are not regularly stocked products, very low quantity, purchased from excess inventory sources OR closeout specials which must be liquidated to make room for new products.  

The tinyCylon is a preprogrammed LED sequencer with 5 red LEDs.

"The tinyCylon is a preprogrammed LED sequencer with 5 red LEDs. The multiple display modes include classic Cylon scanner, evil glowing eyes, malfunctioning/berserk robot and 8 other variations. Modes are selectable with the built in push button. PC board measures 1"x1". The battery holder is covered and includes an on/off switch."

B.G. Micro, 3024 Lincoln Ct, Garland, Texas 75041

Arduino and Freeduino Knowledge

Things are easier than before, there is so much more you can do with this. Starting with a Embedded Project with Arduino type of uC is easy. A PC USB inteface for testing your code. Analog Interface is good for trying out Measurement or Robotic Projects.

Freeduino began as a collaborative project to publish open-source Arduino-compatible production files. The files that resulted from this project allow users to create boards that are 100% functionally, electrically and physically compatible with Arduino hardware. Over time, Freeduino has come to mean hardware that is "Arduino-compatible".

Arduino and Freeduino Knowledge



Freeduino is a free-form version of the Arduino, in that is not developed under a centralized design process.There is no Freeduino team, or anyone to ask permission of: anyone, anywhere, can design and produce a Freeduino product, no questions asked, no royalties paid.

It's sort of like electronic harware anarchy- or democracy, depending on how you look at it. We derived the Freeduino files from Arduino for exactly this reason: to see what the Arduino project would have looked like if it had open hardware distribution and manufacturing.

Arduino and Ethernet Interface

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.

Arduino Open-source Electronics Prototyping



The Arduino Uno is a microcontroller board based on the ATmega328 (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button.

It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.

Arduino Ethernet



The Ethernet differs from other boards in that it does not have an onboard USB-to-serial driver chip, but has a Wiznet Ethernet interface. This is the same interface found on the Ethernet shield.

The Arduino Ethernet is a microcontroller board based on the ATmega328 (datasheet). It has 14 digital input/output pins, 6 analog inputs, a 16 MHz crystal oscillator, a RJ45 connection, a power jack, an ICSP header, and a reset button.

Updated May 14