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.

18 LED dimmable LED lamp

Build it or go for a kit, this is a nice design for a Table or Desktop lamp. You will need to fix in a Enclosure with a Diffused Plastic or Glass Filter Front.

18 LED dimmable LED lamp

18 LED dimmable LED lamp

This circuit is a dimmable white LED lamp array with 18 LEDs. The lamp brightness is regulated as long as the input voltage is above 10.5V. A low-dropout analog voltage regulator is used for a simple and relatively efficient design. The lamp produces enough light to use as a a reading lamp or a small work lamp. – G. Forrest Cook

The 12V DC input voltage is routed through the 1A fuse and the on/off switch. The 1N4001 diode acts as a crowbar device. If reverse polarity is applied, the fuse will blow and the rest of the circuitry will be protected. Power is sent to the LM2941CT voltage regulator IC.

Power this project from sunlight with a CirKits solar power circuit board kit.

Christmas Tree – CircuitStew

The true Christmas Spirit is in giving, You can only give if you have something, right. You can Have when you Acquire Skills, Imagination and a Cheerful Attitude.This will help you Create Things! – dapj

Christmas Tree - CircuitStew

Develop a Skill this Christmas, Build these small LED Trees and give it to people who need a little bit of cheering up.

Christmas Tree – CircuitStew “This was the first and last complete prototype that I made on proto board. This style of prototyping produces circuits that are very difficult to understand, debug, and modify. Because of all the extra work involved they also take forever to assemble. Suddenly I became very interested in designing and fabricating custom pcbs….”

The name CircuitStew refers both to the jumble of electronics presented here and to circuit boards suspended in neon green copper etching solution. – Derek Wolfe

Build Holiday Electronics Projects

“This Christmas, Make and Give to someone that needs it most. That is the real spirit.” – dapj

micro-readerboard Christmas tree ornament displays a short message, one letter at a time, on a bright single-character alphanumeric LED display. In the animation here, the ornament is displaying the word ornament.”

Each ornament is pre-programmed with a list of 36 different short phrases. Every time that an ornament is switched off and back on, it picks a new message from its memory to repeat.

Holiday Projects –

Holiday (Fun Circuits)
25 Light Sequencer using Xmas Lamps – drive 25 small Xmas lights. The lights operate at about 200mA and 3 volts, Anti-Flicker Circuit for LED Christmas Lights. Bells ring Generator –  Three circuit options; Can be synchronized to Christmas tree flashing lights.

Christmas related Circuits – Christmas Flashing-LEDs Badge –  Two-LEDs follow the rhythm of music or speech. Suitable for pins, badges, Christmas decorations. Programmable LED Flashers LED goes to steady state after a preset number of flashes Two simple, wide supply range operating circuits

Christmas Decoration Project
This project flashes 18 LEDs at three different rates and you can use these to create an eye-catching Christmas Decoration. The circuit is kept simple (and low cost) by using the 4060B IC which is a counter and oscillator (clock) in one package.

Ready Kits –

ApogeeKits flashing Christmas tree

Christmas Season Electronic Animated Display Kits
ApogeeKits flashing Christmas tree electronic kit makes a beautiful lighted holiday display. 12 multi-colored LEDs flash randomly. May be powered by a 9 volt battery or a DC power adapter for long term continuous use. User assembly of components and soldering is required.

Grantronics Christmas Tree
“Last November, we published the very popular Christmas Star. This year, our “just for fun” project is in the shape of a tree but we have gone one step further by using bi-coloured LEDs. There are many different light patterns and each LED can produce 16 different colours.”

LED Christmas tree – Learning Electronics

Letter from Chris of PyroElectro.com in 2013 – Happy Holidays!

Here’s a project I know your readers will love! It’s an all-digital-hardware LED Christmas tree we’re calling the Christmas Tree O’Digital Logic.

The tree itself is composed of 64 LEDs built into a spiral sitting on a piece of protoboard. Underneath, the controller uses shift registers and a 555 timer to create two modes of display: a predictable pattern and a random pattern. This should light up any desk or shelf and bring merriment to your readers!

LED Christmas tree - Learning Electronics

We’re also running a Kickstarter campaign to fund our second free online electronics course, “An Introduction To Digital Electronics.” We have just 4 days left to raise $2,124. If you would be so kind as to spread the word about our efforts, we’d be extremely grateful!

To build the tree, we’ll use 63 green LEDs and 1 red LED. Lots of wire will be needed to make the spiral + cone shape of LEDs from top to bottom. To build a random pulse generator, we’ll use some digital logic trickery with a 7404 hex inverter. A 555 timer will be used to drive 8 shift registers, which will control all 64 of the LEDs. Finally, a 4 bit timer should be thrown into the circuit in case we want to slow things down with a divider.

MadLab – Inventive electronic kits

Unique, hands-on electronics workshop for children and adults. In the workshop participants solder electronic components onto specially-designed circuit boards.

MadLab – Inventive electronic kits

MadLab has been made possible through the generous sponsorship and support of the Edinburgh International Science Festival, Zot Engineering and Microchip.

MadLab - Inventive electronic kits

A really useful tool for the budding electronics engineer – a digital frequency meter. New and improved version.

  • input signal range from about 15Hz to 8MHz
  • new feature – bypass switch for low-frequency TTL-level signals from 1Hz
  • internal accuracy +/-1Hz
  • 4 digits of displayed accuracy
  • input conditioning amplifier sensitive to 50mV

MadLab presents an absolute beginner’s guide to electronics. Following this short course will lead you from basic ideas about electronics right up to an understanding of how the simple MadLab kits actually work.

Experiments with the LM2575

The standard buck regulator circuit delivers a +5V output. This is a rather straightforward circuit and will operate with a wide spread of component values. Optimal values should be selected however to get minimal ripple, minimal noise to the power source, maximum efficiency etc. Note that the quiesent current is about 10 to 14mA.

Experiments with the LM2575

Here is a nice way of using this regulator, this can be used for CMOS opamps as you have a -5V too. That means a portable instrument may find this design useful.

The TI Datasheet Layout Guidelines

LM2575 Switching Regulator
LM2575 – Step-Down Adjustable Voltage Switching Regulator with Output Enable

 The Spirit of Hacking and Fixing, Giving back Life to Old Instruments.

Fluke 8050A LCD display replaced with LED seven-segment

“Recently I was able to cheaply buy a second hand Fluke 8050A made in the early eighties. It is a nice 4.5 desktop digit meter, but a typical problem seems to be that the LCD wears out and goes black. Replacement LCD displays are hard to find, not cheap and probably lead to similar problems in due time.”