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Arduino, DYI and how to assemble electronics

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A note on small-signal modeling of SEPIC CM CCM

CAD/CAM *Circuit design *Manufacture and development of electronics *DIY Electronics for beginners

Knowing parameters of small-signal control-to-output transfer functions makes it easier for engineers to design compensation networks of DC/DC converters. The equations for SEPIC can be found in different works and Application Notes, but there are differences. A work has been done to solve this problem.

Simplified design equations for SEPIC with Current Mode control (CM) in Continuous Conduction Mode (CCM) suitable for practical design of compensation networks are shown.

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Total votes 3: ↑3 and ↓0 +3
Views 755
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Controlling Brushless Motors using a Linux computer or a PLC

*nix *SCADA *Computer hardware DIY Electronics for beginners

In this video, we will look at how to connect brushless motor controllers to a Linux computer. Specifically, we will use a computer running Debian. The same steps would work for Ubuntu Linux and other Linux distributions derived from Debian.

I've got a small sensorless brushless motor, and a bigger brushless motor with a built-in absolute encoder. Lets look at how to control those from my Debian Linux computer. Servosila brushless motor controllers come in several form factors with either a circular or a rectangular shape. The controllers come with a set of connectors for motors and encoders as well as for USB or CANbus networks.

The controllers can be powered by a power supply unit or by a battery. To spice up my setup, I am going to use a battery to power the controllers and thus their motors. The controllers need 7 to 60 volts DC of voltage input. If I connect the battery, the controllers get powered up. The small LED lights tells us that the controllers are happy with the power supply.

We need to connect the brushless motor controllers to the Linux computer. There are two ways to do that - via CANbus or via USB. Lets look at the USB option first. A regular USB cable is used. Only one of the controllers needs to be connected to a computer or a PLC.

Next, we need to build an internal CANbus network between the controllers. We are going to use a CANbus cross-cable to interconnect the controllers. Each controller comes with two identical CANbus ports that help chain multiple controllers together in a network. If one of the interconnected brushless motor controllers is connected to a computer via USB, then that particular controller becomes a USB-to-CANbus gateway for the rest of the network. Up to 16 controllers can be connected this way via a single USB cable to the same control computer or a PLC. The limit is due to finite throughput of the USB interface.

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Total votes 4: ↑3 and ↓1 +2
Views 732
Comments 0

DSO138 upgrade

Programming microcontrollers *Circuit design *DIY Electronics for beginners

On Ali, an interesting toy – an oscilloscope called DSO138 is sold for a very inexpensive price. It has already gained quite a lot of popularity among electronics lovers, but the parameters of this device, alas, allow it to be more or less fully used only for debugging very low-frequency circuits. Actually, it is not positioned as a tool, but rather as a DIY-kit for novice electronics engineers.

This "toy" oscilloscope is assembled on the STM32F103 microcontroller, and with a fairly competent circuit design of the digital part, the presence of a fairly decent 320X240-dot color display, and not the most rotten analog path, everything, alas, is ruined by very weak ADCs on board the 32F103. The claimed band of 200 kHz can be recognized as such only with a very large stretch. Yes, it will show the presence or absence of a signal with such a frequency, but it will not be possible to really look at something beyond this.

At the same time, the 103-series has a slightly more powerful brother - the STM32F303, it is almost completely compatible with the legs, but it is significantly better in terms of the parameters we are interested in, there are 4 ADCs on board with a conversion frequency of 5 MHz (6 MHz with a 10-bit resolution). In this scenario, if you use all 4 ADCs in parallel with a 10-bit resolution, you can get a effective resolution of up to an honest 24 MSPS (millions of samples per second). The microcontroller is also inexpensive; you can easily find it on the same Ali for very reasonable money again. It is clear that the idea to change the microcontroller arose almost immediately after I tried this DSO138.

At the same time, if upgraded the toy can turn out to be a completely full-fledged tool that even professionals, not just novice amateurs, could already use. With these thoughts in mind, I decided to try to do something with a Chinese toy in my free time.

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Total votes 5: ↑5 and ↓0 +5
Views 711
Comments 0

RS485 — a standard for industrial networks. What are the main features of the transceiver microcircuit?

Миландр corporate blog Circuit design *Manufacture and development of electronics *Electronics for beginners Systems engineering

When building a network for communication between a large number of devices, one may think: what interface to choose? Each interface has its own pros and cons that determine its application: CAN — Automotive, RS485 / RS232 — Industrial, Ethernet — Consumer Electronics / Server. What features of the transceiver microcircuit help to protect against many problems during installation and operation? How is the process of measuring and researching of transceiver microcircuits going on? New RS485 microcircuit is ready to get to market!
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Total votes 4: ↑4 and ↓0 +4
Views 623
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Circuit design *Manufacture and development of electronics *DIY Electronics for beginners

Gyrators are impedance converters usually used to simulate inductance in circuits. Though they are rarely used in discrete electronics, they are interesting circuits looking like pole dancers in pictures. There are studies on gyrators, but still something is missing, so it is interesting to do another one.
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Total votes 4: ↑4 and ↓0 +4
Views 982
Comments 0

Active Termination Drivers

Circuit design *Manufacture and development of electronics *DIY Electronics for beginners

The easiest way to build a driver with specified output impedance is to use an amplifier with high load compatibility and add a resistor to its output. The penalty is a voltage drop across this resistor, so there is power loss and we need a higher supply voltage. If our driver is able to deliver the same voltage and current to the same load, but the extra resistor will have a lower value, our device will be able to deliver the same output power at a lower supply voltage. Less power losses, less heat, and longer working time when a battery is used.
There is an idea how to solve this problem: active termination. We can synthesize the output impedance!

Now when we know what we want, go to design our drivers!
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Total votes 6: ↑6 and ↓0 +6
Views 1.6K
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Compensation for Error Caused by Limited Gain-Bandwidth of Operational Amplifiers in Low-pass Filters

Circuit design *Manufacture and development of electronics *DIY Electronics for beginners
Amateur vs Pro

An operational amplifier has the internal compensation circuit for stability which limits its working bandwidth. Frequency response of the compensated Op Amp has slope of −6 dB/octave or −20 dB/decade. Unity gain frequency defines the bandwidth where the Op Amp is able to amplify a signal. If we multiply the gain and frequency at any point, the result is the same, allowing us to use this parameter to select the appropriate Op Amp. It is called Gain-Bandwidth Product, GBW or GBP. The limited open-loop gain introduces a closed-loop gain and phase error.

But we want to optimize our circuits, right?
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Total votes 8: ↑8 and ↓0 +8
Views 1.7K
Comments 0

Common misconceptions about space-grade integrated circuits

Circuit design *Manufacture and development of electronics *Popular science Astronautics Electronics for beginners

Space exploration was always fascinating, and recent developments have reignited the interest to the heights never seen since the last man stood on the Moon. People argue about Mars exploration and features of spaceships as their grandparents would’ve done if the internet existed fifty years ago. I’m an electronics engineer working in the aerospace industry, so I know a thing or two about the technical background of this stuff — and I see that these things aren’t common knowledge, and people often have significantly skewed ideas about the reasons behind many things and decisions. Namely, I’d love to speak of some misconceptions about radiation hardened integrated circuits and the means of protection from radiation-induced damage.

So, let's start our journey
Total votes 15: ↑15 and ↓0 +15
Views 15K
Comments 35

GoROBO: an educational initiative from the ITMO University startup accelerator

ITMO University corporate blog Robotics development *Start-up development Robotics Electronics for beginners
GoROBO is an ITMO University project through and through: one of the co-owners graduated our mechatronics MA program, and two other employees are current postgrad students.

Let’s talk about the educational environment they want to create, why they chose to build such an unusual startup, and what awaits GoROBO clubs in the future.

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Total votes 5: ↑5 and ↓0 +5
Views 604
Comments 0

Tech Insights: Are LED filament-lamps so good?

Gadgets Computer hardware Electronics for beginners
Saluting my LED lamp fans!

Today we will talk about the palpitating and extremely popular subject in recent years — filament LED (Light-Emitted Diode) lamps. Numerous articles have been published here on Habr (1, 2, 3) and on the web, but none of them tells us a word about in-depth analysis of the lamps (what is actually inside) and comparison of their temperature characteristics. Therefore, especially for you — my dear LED-lovers — I conducted a detailed analysis of such lamps from different manufacturers, including temperature measurement of LEDs themselves.

Afterwards we will try to answer the question: are filament lamps as good as marketers present them to us?

Disclaimer: this is my very first attempt to translate and adopt an article from Habr into English, so I will ask you to give a fruitful feedback and correct some mistake if any present.
Shock, thrill and scandals!
Total votes 9: ↑8 and ↓1 +7
Views 2K
Comments 0

Board game for learning the basics of electrical circuits. Why not?

DIY Logic games Electronics for beginners

I made the “electric” designer of… cardboard. Alas, the project still remains at the prototype stage, not developing into an industrial “physical” look and is waiting for its time (and investor).

But I decided to go further — once we started making cardboard, we’ll bring the situation to its logical conclusion — we’ll make a complete cardboard board game, but with an electric setting and a learning effect. There were a lot of options — starting from a simple “walker” and ending with Ameritrash from a zombie with electron movement and vicious short circuits and swollen capacitors.

As a result, I decided to dwell on a logical abstract, since the schematics of electrical circuits are very suitable for it. Said and done — as a result of the first iteration, the game “Circuit” was born.

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Total votes 12: ↑11 and ↓1 +10
Views 3K
Comments 1

Chemistry lesson: how to expose a microchip's crystal for photography

Reverse engineering *Manufacture and development of electronics *Chemistry Electronics for beginners


If you have dabbled into microchip photographing before, then this article will probably not offer much to you. But if you want to get into it, but don’t know where to start, then it’s exactly for you.

Before we start, a fair warning: while the procedure is quite entertaining, at first it’ll probably be physically painful. The chemicals used during the process are toxic, so please handle them carefully – that way it’ll still hurt, but less so. Also, if you have even a slight amount of common sense, conduct the procedure in a fully-equipped chemical laboratory under supervision of trained professionals: we’ve had to deal with people who tried to do it at home immediately after reading the guide. And finally: if you don’t know whether you need to pour acid into water or water into acid without a Google search and don’t realize what this lack of knowledge will entail – stop reading this immediately and go to a chemistry 101 course in a local college or something.

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Total votes 25: ↑24 and ↓1 +23
Views 1.3K
Comments 0

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