Heathkit was a well known supplier of electronic kits from 1947 through the early 1990's (although no new kits were developed after 1986). An incredible number of kits were offered including test equipment, amateur and SWL radio, audio, televisions, computers, robotics, automotive and other items difficult to categorize.
Heathkits - Learning with Practical Electronics
THD Improvement kit for IG-18 series audio generators
"The meter buffer is a crucial part of improving the THD specification of the IG-18. The non-linear loading of the analog output can create additional harmonic components due to the non-linearity of the diodes used to drive the meter."
History and Antiquity
In 1947, Heath introduced its first electronic kit, an oscilloscope that sold for US$50 -- the price was unbeatable at the time, and the oscilloscope went on to be a huge seller.
The Heathkit Virtual Museum, a tribute to the Heathkit era-a time when building electronic kits was a favorite pastime for many electronics hobbyists. This commemorative virtual showcase takes you back to the Heathkit age which began in the late 1940's and lasted through the early 1990's.
Then you ought to look around at Bill Wilkinson's Heath Company Page if you want to know more.
Hobby Electronics, Amateur Radio, Do it Yourself Projects, Kits.
Hobby Hound

Tuesday, December 08, 2020
Heathkit Educational Kits
Runoffgroove - DIY Articles and Schematics
Runoffgroove - DIY Articles and Schematics
Some Entertaining Projects are -
Mr. EQ - A simple, yet potent DIY equalizer. Schematic, PCB/perfboard layouts, and photos.
Little Gem - Two 9v battery-powered amps based on the LM386. Schematic and PCB/perfboard layouts.
Eighteen - The Marshall 18W adapted for use as a distortion stompbox. Schematic, PCB/perfboard layouts, and photos.
Tonemender - An ultra-flexible tonestack with clean boost. Schematic, photo, and PCB/perfboard layouts.

Thor - The legendary Marshall 100W Super Lead adapted for use as a distortion stompbox. Schematic and PCB layout.
The Thunderchief project, released in March 2004, was the first runoffgroove.com circuit that was developed using the tubes-to-FETs process. Enlightened and inspired by Doug Hammond's excellent Meteor circuit, we used the same approach in an effort to capture some of the legendary magic of the Marshall Super Lead. The circuit's performance pleased us, but there were issues.
Splitter-Blend - Dual parallel buffered effect loops with blend control. Schematic and perfboard/PCB layouts.
Professor Tweed - The Fender Princeton adapted for use as a distortion stompbox. Schematic, PCB/perfboard layouts, and photos.
Friday, December 04, 2020
SpikenzieLabs - Kits and Projects
It is nice to see many building solutions over the Arduino base like this Prototino. Both hardware and software of Arduino are Extensible. This gives opportunity for New tools and Solutions over this compact system Framework.
One Idea can be an Arduino with a CPLD and Universal I/O driver for robotics. This can come with a Visual IDE which is close or better than the old Visual Basic 6 in usability.
An Youngster can just Drag Drop Components and Link them to build his Robot or Home Automation Solution. Robotics Designers can have the option of looking at the code/hex if needed.
delabs Notes
Prototino an Arduino clone for Prototyping
The Prototino is an Arduino clone with a built in prototyping area.
Designed to make a permanent version of your project once you have
perfected it on a breadboard but without the expense of embedding your
original Arduino into your project.
The Prototino also makes your project more reliable and robust. With the prototyping area integrated into the board with the microprocessor, your project will have fewer boards and fewer wires, and because of that, fewer mistakes and fewer shorts.
SpikenzieLabs - Kits and Projects
6135 de Maisonneuve West, Suite 12, Montreal, QC H4A 2A3, Canada.
Sunday, November 01, 2020
Linear Regulated Dual Polarity Power Supply
"This document describes how to construct a dual polarity linear power supply which can be configured for any positive or negative voltage between 1.2-35V. A power supply is the fundamental building block of all but the simplest of electronic devices. It converts the alternating current (AC) from our wall outlets into direct current (DC) at some specified voltage. Because so many electronic devices need DC to function properly, a versatile power supply is the perfect addition to a hobbyist's collection of test equipment. " from Wayback Machine
Linear Regulated Dual Polarity Power Supply
"There are two versions of the power supply which are fundamentally very similar. The first is a compact fixed-voltage supply measuring 2.9" x 2.2", which is well suited for applications requiring small size and modest current capacity like TTL logic circuits or op-amp based projects such as active crossover networks. The second is a larger (4.6" x 2.25") variable supply sporting more robust heatsinking, and the regulators are positioned such that they may be mounted to a large chassis heatsink for even greater heat dissipation. And since this version of the supply is variable, it is ideal for experimenting. See the photographs near the bottom where I built one into an ATX power supply chassis."
Wireless Phone and your Arduino
Using some of these Shields you can gift Smartphone Power to your Arduino. Create a Home Automation System with a Smartphone App control. An interactive Robot with SMS. Create a Process Automation System with SMS Alerts too.
3G + GPS shield for Arduino - https://www.cooking-hacks.com/

Connect to high speed WCDMA and HSPA cellular networks. Make web interactive project like the "Internet of Things". The module counts also with an internal GPS what enables the location of the device outdoors and indoors.
- HTTP and HTTPS (secure mode) navigation, download, upload to web server.
- FTP and FTPS (secure mode) protocols are also available.
- Send and receive mails from Arduino using the SMTP and POP3 clients.
Wide Skill Spectrum by Building a Robot
Wide Skill Spectrum by Building a Robot
Basic Mechanics— Describes basic mechanics, friction, and the simple machines that comprise the building blocks of more complex machines, like robots.
Sensor Design - Without sensors, a robot is just a machine. Robots need sensors to deduce what is happening in their world and to be able to react to changing situations. This chapter introduces a variety of robotic sensors and explains their electrical use and practical application.

Robot Control - The most common kind of robot failure is not mechanical or electronic failure but rather failure of the software that controls the robot. For example, if a robot were to run into a wall, and its front touch sensor did not trigger, the robot would become stuck (unless the robot is a tank), trying to drive through the wall. This robot is not physically stuck, but it is "mentally stuck"
delabs Notes
When you build a robot, you are dealing with Mechanical, Electrical, Electronic and Computer Technologies with the Interfacing.
The improvement in the Wireless Communication, Low Power Hi-Speed Semiconductors coupled with compact gigabytes of Flash/HDD may help build a Creative Robot with a smart brain.
Tuesday, October 06, 2020
Hobbyist Dream - Weller Soldering Iron
Rework/repair tools, soldering guns and irons and accessories. 60 Watts, 240v Temperature Controlled Soldering Station. This is My Iron and a stand i made.
There’s no mystery about soldering; it’s as easy as you make it. Follow a few simple rules, and metal joins metal like magic. This little book gives you the rules in pictures—with as few words as possible. All you need do is follow through, step by step, and youll solder sound joints.
Weller Soldering Tips : Your Guide to Easier Soldering
History - "Cooper Industries origins extend back more than 170 years to a small iron foundry in Mount Vernon, Ohio, started by brothers Charles and Elias Cooper in 1833. Today, Cooper Industries has become a leading worldwide manufacturer of electrical products and tools and hardware."
Electronic Product Production and Manufacturing
Some Features
- PU240T power unit,
- TC201T soldering pencil,
- PH1201ESD stand and sponge
- A lighted rocker switch indicates on/off status
- Comes with PTA7 tip
- ESD safe to protect sensitive components
QRP and homebrew by DL2YEO
QRP and homebrew by DL2YEO
- Front Panel Design
- Some useful Tables
- 13.8 V / 15 A from a PC
- 250 W S.M.P.S.
- Analogue Frequency Display
- Oscillators
"The electronics industry uses several methods for labelling front panels and enclosures, including screen printing, press forming, erosion, lasers etc.. The common factor of these techniques is that they are generally beyond the home constructor. Having these parts specially made commercially can be very expensive, and the only alternative is standardized scales and fonts."
Sunday, October 04, 2020
PY2WM JK De Marco Projects
An Amateur Radio Enthusiast from Brazil. JK De Marco. In these pages Hams will find his ideas on QRP, Antennas and Complete circuits.
PY2WM JK De Marco Projects
“One test result is worth a thousand expert opinions”. This has been attributed to a range of people, but most authoritatively to Wernher von Braun, the rocket scientist.
A 40 dB RF Attenuator -
"To measure power of a high power transmitter, or to be able to observe the output signal on an oscilloscope or spectrum analyzer, it is necessary that the signal is attenuated in accordance with the instrument, while it must be ensured that the transmitter is "seeing" the correct impedance. So it requires an attenuator that works with three ports (input, output, and output attenuated), all while maintaining the correct impedance of 50 ohms.
The circuit assembly and is shown here in EMRFD and also in the QST. When properly calibrated can be used for precision measurements in section 0-500 MHz, or a a calibration capacitor C1, can be used for the range of 0-50 MHz with reliability."
Other Projects and Ideas
- Simple Homebrew Coil Winding Machine
- Qrp-Br Spectrometer
- Simple ESR meter
- Swr Power Measuring mW To KW
- 5 Volts Reference Voltage Calibrator
Saturday, September 05, 2020
PJ Tool & Supply - Papa John’s Toolbox
PJ Tool & Supply - Papa John’s Toolbox
The Helping Hands magnifier is a great hands free device for holding small items in a fixed position for soldering and other intricate work.
Helping Hands Magnifier

PJ Tool & Supply
40-H Corbin Ave. Bay Shore, NY 11706, USA
Thursday, September 03, 2020
Step Down Capacitor - No Heat
This circuit has been drawn from my memory and i have not tried it out again, just see if it is ok and then try. You should use the fuse of 100mA a slow blow if you want but it is very important. This circuit has to be enclosed in a plastic sealed enclosure to avoid contact.
Mains Voltage Indicator with a LED

Tuesday, September 01, 2020
Cornfield Electronics - Mitch Altman
Cornfield Electronics - Mitch Altman
Solder your ArduTouch kit together, and it works! You can make way wonderful music, sound, and noise.

Use the ArduTouch Library or hack the existing sketches to create your own cool synthesizers.
The documentation is getting good enough to learn how to use Digital Signal Processing (DSP) to make your own sounds for your own projects.
Cornfield Electronics, Inc.
1800 Market St. #123 San Francisco, CA 94102, USA
Thursday, August 13, 2020
Beetle Robot guided by Light
I had built many physics projects like weighing scale, gramophone, telegraph system, crystal radio. I will try to explain these later. Calling bells, gears and magnets from the flea markets my source of electricity & magnetism.

I read a hobby book from UK for children. It was a Beetle Car Bot, with four wheels and 4 light sensors. It could be LDR or photo-transistors, i do not remember. The light sensors were at the four corners of the car. The maneuvering was by variation in the speed of each wheel. It was based on germanium transistors mostly.
Four large lamps like 40W, had to be mounted on the ceiling, at the four corners of the room. By turning on and off these lights, this bot could go anywhere in the room. The whole book with pictures was dedicated to one bot and how-to build one.
Now that we have PIC and AVR; we can use Dimmable LED Lightning arrays to guide the bot. The challenge is in the mechanics of the bot, we have to forget that we have wireless for some time. Try this out.
Friday, August 07, 2020
GainClone Chipamp Audio Amplifier
GainClone Chipamp Audio Amplifier
The Gainclone is probably the most commonly built and well-known amplifier project amongst hobbyists. It is simple to build and involves only a few readily accessible, inexpensive parts. As an amplifier it is highly regarded by many in the DIY community.

GainClone Amplifier Rod Elliott (ESP)
"The amp is based on the Project 19 PCB, so uses a pair of LM3876 (or LM3886) power opamps, run from a ±35V supply. ...........The power supply is conventional in almost all respects. I used a 160VA transformer, a 400V 35A bridge rectifier, and a total of 20,000uF per supply rail - 4 x 10,000uF caps in all."
Recording Technology History
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 - https://www.aes.org/aeshc/

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.
Friday, July 10, 2020
DIY Radio Control Electronic Projects

The "Simple-Timer" includes a fairly accurate timer that is programmable (via pushbutton) by the user and can be programmed to time a 5, 10, 15, 20,25 or 30 minute event. When the timer/switch is enabled (tap small pushbutton), the onboard LED indicates the output is active by lighting solid (the circuit also outputs the same voltage as your supply/battery voltage using a PN2222 NPN transistor or a high current MOSFET).
Tom's Home Automation with X-10 Schematics Collection
Electronix Express - For Schools and Industry
Electronix Express - For Schools and Industry
Some of the products they supply include Anti Static Products, Toolkits, Soldering related, Inductors, Logic Probes and Pulsers.
A Benchtop Multimeter, 4 ¾ digit, 40,000 count true RMS AC with Built-in USB & RS232 Interfaces.

Bench Digital Multimeter DM422B
Other features -• Data save and recall with software, Triple display, (main, sub-left, sub-right), 40 segment bar graph display, duty cycle, Temperature function.....
True RMS, USB & RS232 Model
Electronix Express
900 Hart Street Rahway, NJ 07065, USA
Monday, July 06, 2020
Makerbot - 3D Mechanical Prototype Synthesis
Makerbot - 3D Mechanical Prototype Synthesis. https://www.makerbot.com/
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
Thursday, May 14, 2020
Amplifier.cd - measuring instruments - audio
Amplifier.cd - measuring instruments - audio

A Tutorial describes fundamental ideas of electro-technology and the general amplifier and audio technology. The test equipment gallery shows measuring instruments - older, historical and partly new.
Obsolete Test Equipment Gallery
The gallery shows measuring technique, with which electronics are developed. Some are special and classic devices, which are still in use and some already represent a historical value. Many of these devices have special functions, which are very popular. The side does not intend to show newest test equipment from the portfolio of the manufacturers (some devices excluded).
Saturday, May 09, 2020
One Watt Mains LED Lamp or Tubelight
Home Made Circuits.
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.
Monday, May 04, 2020
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.
Monday, March 16, 2020
The Hardware Book - HwB
HwB - The Hardware Book - Joakim Ögren

Some Topics
- Universal Serial Bus (USB)
- Binary conversion
- Serial Port Loopback (9 CheckIt)
- Ethernet 10/100/1000Base-T
Thursday, March 12, 2020
Labcenter Electronics - Proteus Design Suite
Labcenter Electronics - Proteus Design Suite
Co-simulation of microprocessor software within a mixed mode SPICE simulator.
- Available for PIC, 8051, AVR, HC11, ARM7/LPC2000 and Basic Stamp processors
- See your code interact with simulated hardware in real-time.
- Interactive peripheral models for displays, keypads, etc.
- Over 8000 analogue and digital device models.
- Extensive single step and debugging facilities including system wide diagnostics.
- Works with popular compilers and assemblers.

Proteus Virtual System Modelling (VSM) combines mixed mode SPICE circuit simulation, animated components and microprocessor models to facilitate co-simulation of complete microcontroller based designs. For the first time ever, it is possible to develop and test such designs before a physical prototype is constructed.
Tuesday, March 03, 2020
PCBWay - PCB and Assembly Services
PCBWay - PCB and Assembly Services
PCBWay is a PCB manufacturer in China. They offer the most cost-effective PCB prototype services. The also manufacture larger quantities and provide product assembly services.

Axiom: 100kW motor controller
It is a 3 phase motor controller. It takes a DC voltage and generates 3 sinewaves for driving a motor, conceptually similar to those small ESC for drones and bikes. The difference is that this particular setup can safely work with a 400V battery, flowing 300Amps all year long.
"In order to give support to many electronic enthusiasts who want to build projects but do not have enough money, PCBWay is the first manufacturer who gives them at a low price."
Six reasons why PCBWay is the best PCB manufacturer
Considering a large proportion of electronics enthusiasts are students or beginners, PCBWay has created dedicated channels for sponsorship to encourage these electronics enthusiasts to create their own projects. PCBWay has sponsored more than 1000 projects so far which include robots, rockets, racing cars and so on. PCBWay has also sponsored Makerfaire, SHA2017 and other activities.
(Above content provided by the sponsor firm. Refined and moderated by delabs)
Friday, February 14, 2020
Fritzing is Product Design or EDA in Simplicity
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
What do you get? The ultimate beginners book teaches you everything you need to know through a series of practical--yet playful--exercises. And that playfulness is the key! There is a paper robot who can turn his head; a fortune teller who is (of course) never wrong (no guarantee on that); a dinosaur who relays the news on your Twitter stream and a pong game on a big LED matrix display.

Fritzing's goal is to provide easy tools for documenting and sharing physical computing projects, producing layouts for Printed Circuit Boards (PCB) and teaching electronics.
Monday, February 10, 2020
Museum Of Electricity - Charles Brush
Museum Of Electricity - Charles Brush
The General Electric Company was formed in 1892. It was the result of a meger between the Edison General electric Company and the Thomson-Houston Company, which themselves incorporated several other companies.

Electricity, technology, and lots of arcs and sparks!
Museum Of Electricity contains Vintage Electrical and Historical images and description. They include the Edison Lamp, Tesla Coils, Lightning and Atmospheric Electricity and the .....
Amazing Jacob's Ladder
So how do they work? First two conductive metal rods are positioned in a rough “V” shape with a slight space between them at the base. A sufficient voltage differential is provided from a high voltage transformer to breakdown the air in the gap between the rods.
Wednesday, February 05, 2020
Single Digit Voltmeter with LM311

First bear it in mind that it is a single digit voltmeter which is 0-9 counts only on the positive side, that is it can measure +0 to +9V DC +/- 1V error. That may not be practical for the cost of the components above. It may be used as a toy logic probe. The reason for the circuit is not for usage, but to give design ideas. The methodology used is Gut Feel - Thumb Rule method.
Tuesday, January 21, 2020
Lauriers Handy Dandy Little Circuits
Some of the Projects are Temperature Controlled Soldering Iron, Digital Capacitance Meter, DC Power Supply, Six-digit Freg.Counter, RPM Meter, Wirekess Remote Control Switching.

Some circuits are Microphone Pre-amplifiers, FM Transmitters, Transistor tester, Phono Pre-amp to Sound card, Signal function generator, Car Pseudo Alarm project, Percussion Generators, Audio Equalizer and Metering a Power Supply.
Laurier Gendron, Coquitlam, B.C., Canada.
Elliott Sound Products - The Audio Pages
Elliott Sound Products - The Audio Pages

- Projects - Complete listing of ESP's free project and design articles
- Articles - Informative articles about audio, building projects, and electronics in general
- Buy PCBs for ESP Projects - boards supplied have very comprehensive documentation.
It is by Hobby and DIY - Do it Yourself, Education Starts even without books. Then you need to read to enhance your abilities to Design your own.
In order to compensate or enhance your education, you need to work at a small shop as an apprentice even as a student, not for the sake of project work alone. An Evening job at a factory or a home mini workshop-lab is very essential for obtaining the skills - Solderman 1702
Strippenstrolch - Elektronikbasteln
Strippenstrolch - Elektronikbasteln
LED Lighting Projects, Learn Electronics, Basic Circuits and how they work. All in German.
"In Germany one finds this designation now and then for an electrician on the work. Particularly in the winter, if it is still dark in the morning, one often sees "Strippenstrolche" with its building lamp on the building site:"
Combination of Rain and Sun Harvesting
"The inspiration for a self-sufficient toilet flush was now close at hand: I thought at first to work with a power supply that provides me the 12V to the pump. But as a power supply would idle constantly consume energy, I rejected this solution. I have long experimented with solar power, so I decided, now a solar system for our toilets to build. On the flat roof of our garage I installed two 12V - 55Wp - solar - modules (Conrad Electronics). This I switched in parallel."
"As a solar storage currently serves an ordinary car battery 45Ah (later 3 pieces with a total of 135 Ah). The charging control acquires an 8A charge controller (Conrad). So all very simple."