• Tech Ads

Make a Shake LED Flashlight

I  was enlightened about this Battery Less wonder. This is a boon for rural areas and an emergency tool which depend only on your will and your tendons. I found this bright flash of information when i was looking for supercap vendors.

Learn about Supercaps, dynamo and White LED

Richard J. Nelson on the LED Forever Flashlight. – The future of low power lighting is in the use of the Light Emitting Diode, LED. Sooner or later you will buy one or more LED lights or lamps. The two primary advantages of an LED light source is it’s efficient light generation (exceeding that of fluorescent lamps) and long life, typically 100,000 hours. That is 50 to 100 times more life than most of the bulbs in your house.

Learn about the Eternal Torchlight

This is a Linear Dynamo LED Torch which uses a SuperCapacitor to store the energy. Easy to repair and maintain if necessary.

It uses no batteries and requires only the single LED included. You can even leave the flashlight unused in your car’s glove box for years and you’ll always get that all-important light when you need it most. Forever Flashlight lll pays for itself quickly by saving you the cost of batteries and bulbs.

Hobby Circuits – Bill Bowden

Bill Bowden’s Circuits is one of the oldest Web Reference, it was hosted by CompuServe homepages and later moved to his own domain website.

A small collection of electronic circuits for the hobbyist or student. Site includes over 100 circuit diagrams, links to related sites, commercial kits and projects, newsgroups and educational areas.

Hobby Circuits - Bill Bowden

Most of the circuits can be built with common components available from Radio Shack or salvaged from scrap electronic equipment…….

Hobby Circuits – Bill Bowden

Some of the Highlights in this website

  • 32.768 KHz Oscillator Using A Common Watch Crystal
  • 40 LED Bicycle Light (555 Timer – 6 volt)
  • Descrete LED fading circuit using 5 transistors
  • Mechanical Wall Clock Quartz Synchronizer
  • Neodymium Magnet Single Pole Motor
  • Variable Voltage and Current Power Supply
  • Micro Power AM Broadcast Transmitter

Circuit Exchange International

There are ten categories of schematics, a unified circuit analysis, design and theory page, and also a practical electronic section. The simulation section features the “TINA” and “Circuit Maker” programs. (this is a first generation website )

Circuit Exchange International

Some interesting sections are Alarms & Security Circuits, Control & Interfacing, Radio Circuits, Power Supplies & Circuits, Timing Circuits.

Circuit Exchange International

 

First created back in March 1999 and intended for electronics hobbyists, engineers and enthusiasts everywhere. Currently there are 310 schematics divided into 11 categories. Also included are tutorials, design and simulation sections.  – Andy Collinson

Flashing Mains Neon Lamp

Here is a Neon Flasher circuit (untested) for a user request at Circuits FAQ. This can be built into a switchboard or a gadget for indicating Live Power.

D1-C1 form a simple half-wave rectifier, The Cap charges to peak voltage and can store charge for a long time if there is no bleeder. So while building it take extra care. This forms a DC supply across C1. C1 is a Plastic High-voltage cap, IN4007 has a 1KV rating, so it is ok for 230V rectifier.

R1 Charges C2 and when C2 reaches 60-80V depending on Neon, the neon breaksdown. C2 Discharges, Neon Recovers, The C2 starts charging again and so on and on. It Oscillates, probably in a Ramp Waveform. But do not use your Scope on this, you will regret it a lot. This is a live circuit and needs a special probe.

“Oh, i will put the probe it in 10M mode” will not do. The ground clip of the probe goes to Electrical Earth which is ‘connected’ to Neutral in the mains wiring. So you put the earth crocodile clip on the live point. There will be flashes and fireworks. So you need to isolate both terminals of scope. Please use your costly equipment with great care.

For the 1 Meg use two 470K in Series for 230V AC, that is safer. The circuit is live, so take precautions. The 0.47 Micro Farad can be increased if you want a slow flash. If the Mains 50/60 Hz Flicker is too much, the 1 uF can be made 2 uF, or use 4 – 1N4007 as a bridge rectifier.

From Schematics of delabs

User Feedback –

R1 of 4.7M and C2 of 0.47uF Works well at 230V AC. Try your own Combination. Less than 1M may damage Neon.

Jason Neals DIY Audio and Electronics

Dual Polarity Power Supply
Two versions of a dual polarity power supply with printed circuit board artwork. The supplies are built around the popular LM317 & 337 complementary voltage regulators which offer very high ripple rejection as well as short-circuit and thermal protection.

Jason Neals DIY Audio and Electronics

Microphone Preamplifier
A battery-powered microphone preamplifier and microphone wand for acoustic tests and recording. The preamplifier features 20dB of switchable gain and a clipping indicator,

Jason Neals DIY Audio and Electronics
An interesting website with many photos of electronic projects. There are not many projects but the description and photos and documentation are very useful for learning the art of circuit design.

Low Cost AM FM Stereo Receiver

This was a National Semiconductor Application Note, now TI. – Low Cost IC Stereo Receiver.

AN-147 Low Cost IC Stereo Receiver

Some Highlights

The LM3089 FM IF System does all the major functions necessary for FM processing, including a three stage amplifier/limiter and balanced product detector, as well as an audio preamplifier.

FM stereo demodulation is accomplished by the use of the LM1800 phase locked loop, thereby eliminating the need for external coils.

The AM function of the receiver is done completely with the LM3820 AM radio system. While designed for 3 section tuned superheterodyne application.

The LM382 dual preamplifier was selected for its minimum parts count and low noise capability.

Panel meters are employed in the FM system for both signal strength and center tuning, allowing for easy and accurate tuning. A directly driven LED offers immediate indication of FM stereo reception.

Low Cost AM FM Stereo Receiver

A single transistor tone control circuit was designed as the optimum cost/performance trade-off. The transistor is configured in a shunt-shunt feedback design, allowing gain variations between input functions.

The stereo power section, consisting of the LM378 dual audio amplifier, delivers 3W/channel with total harmonic distortion (THD) less than 1% and 4W/channel with THD less than 10%,

ELM – Electronic Lives Mfg

“My hobby has been a present occupation as it is because I liked electronics relatings since I was little. Railroad, anime, comic and TV game as well. As for programming in the hobby, because they are electronic handicraft” – Chan Japan

ELM – Electronic Lives Mfg

ELM - Electronic Lives Mfg

Chan has many projects for learning the use of Microcontrollers. even Instruments. You can even study about how to develop a PC Interface for electronic design you made. Then there are pages on Audio and Video Processing. See the LED Lantern and the Capacitance Meter too.

DC Servomotor Controller

This is an experiment on the closed loop DC servomotor control system (SMC). It will able to be used for practical use with/without some modifications.

Desktop Line Following Robot

In lines of the Japanese Tradition of Miniaturization, chan has built a tiny line following robot which can run on the desk, A toy that is one fifth the size of the line following robots, seen these days,