Here is an app note from Maxim describing the various SMPS regulator topologies for battery powered systems:
This tutorial presents an overview of regulator topologies for battery-powered equipment. The discussion covers linear regulators, charge pumps, buck and boost regulators, inverters, and flyback designs. The importance of peak current is explained, and schematics of each topology are shown.
App note: Regulator topologies for battery-powered systems - [Link]
Op-amp Based Preamp for Moving Magnet (MM) and Low Output Moving Coil (LOMC) Phono Cartridges
This project is a departure from that of my normal sort. It is based around an operational amplifier (op-amp)… Yup I’ve transgressed to the dark side. Actually I have nothing against integrated circuits (IC) or solid state devices and in fact use a number of solid state components in my designs. This project is for a relatively simple high performance phono preamplifier that can handle both moving magnet (MM) and low output moving coil (LOMC) cartridges. The basis for the project was a temporary need to have a LOMC preamp in addition to the valve (vacuum tube) ones I have to study low noise performance. Without trying to start any arguments, I have found that it is a lot easier to make a low noise high gain solid state circuit than it is to do the same for valve circuit of similar capabilities. The circuit I came up with is pretty much like many common op-amp based phono preamplifier circuits.
DIY OPA2134 RIAA Phono Preamplifier (MM / MC) - [Link]
This collection of circuits provides step-up voltage regulation for single cell and dual cell Alkaline, NiMH, and Li+ battery driven applications. Regulate your battery driven app with an efficient converter from Maxim.
Your battery-powered application needs regulation. This collection of circuits provides step-up voltage regulation for single- and dual-cell Alkaline, NiMH, and Li+ battery-driven applications.
A simple 1A step-up converter in a tiny WLP package that can be used in any single-cell Li-ion application. This IC provides protection features such as input undervoltage lockout, short circuit, and overtemperature shutdown.
The input voltage of these circuits range from 0.7V to VOUT and they have a preset, pin-selectable output for 5V or 3.3V. The outputs can also be adjusted to other voltages using two external resistors.
CometCAD is a simple electronics circuits CAD software able to capture schematics and layout PCB. Is free for use, but there are some limitations.
CometCAD is circuit schematic and layout editor program for Windows - [Link]
In this introduction Dave explains what LTSPICE is and how to do the simplest of the SPICE analysis options – basic DC operating point analysis. Also how to draw basic schematics, display voltages and current on your schematic, and a beginner few traps to avoid.
EEVblog #516 – LTSPICE Tutorial – DC Operating Point Analysis - [Link]
Viktor blogged about his bipolar stepper motor driver based on Texas Instuments’ LMD18245 build:
After extensive research on the internet I decided to make a bipolar stepper motor driver based on Texas Instuments’ LMD18245, which is a 3A, 55V DMOS Full-Bridge Motor Driver. It incorporates all the circuit blocks required to drive and control current in a bipolar stepper motor.
Bipolar stepper motor driver circuit with LMD18245 - [Link]
Humidity can be measured by various sensors, but sensors SHT from company Sensirion add many benefits moreover.
To be exact, a word „sensors“ is not a suitable expression in this case. As SHT series sensors contain on one chip humidity and temperature sensor, precise supply, low noise linear amplifier, AD converter and a serial interface, they represent a ready-made “device”. Moreover, they´re calibrated, thus to get an exact value it´s only necessary to read out data through a serial interface. In case of SHT2x series, it´s a standard, easy-to-implement I2C interface.
Sensirion sensors SHT2x series was more in detail introduced to you in our article „New sensors Sensirion will take you only 3x3mm on PCB!”, that´s why we´d like to bring you mainly few tips for simplification of development now.
Area of relative humidity and physics of water vapors is quite ample and into its introduction will initiate you the document Introduction_to_Relative_Humidity. Don´t be scared of many quotations, which you´ll find there – fortunately in common praxis we usually manage it with values of relative humidity and a dew point, which can be found together with code examples in Humidity_at_a_Glance.
As humidity sensors are very often used in residential places for regulation of heating and ventilation, also useful can be information about influence of humidity on a thermal comfort. For a practical usage of sensors it´s also important their placement on a PCB and a good access of air, what is in detail described in the document Sensirion_Humidity_Design_Guide. SHT2x are intended for 3VDC power supply, that´s why when using in 5V applications, you can face a problem of different voltage levels. This can be easily solved for example by a circuit described in the document SHT2x_5V_Supply_Embedding.
The program itself doesn´t need to be developed “from zero”. Examples can be found in the document SHT21_Sample_Code and SHT2x_Electronic_Identification_Code. Detailed information about testing and specification of SHT sensors can also be found in documents Sensirion_Humidity_Sensor_Specification_Statement and Sensirion_Humidity_Testing_Guide.
SHT25 – humidity and temperature precisely in every season – [Link]
by Stephen Evanczuk
With Apple’s anticipated announcement on September 10 of not one but two new iPhone models, speculation on the features and designs of the new iPhones has revolved around expectations for faster, more feature-rich smartphones built around Apple’s recently released iOS 7, featuring its new “flat-design” look. In fact, even the product name is matter of conjecture at this point, but economics suggests that the new phones will emerge as variants of Apple’s current flagship, the iPhone 5.
As a result, rather than expect to see an “iPhone 6″ with significant hardware changes, a safe bet lies with expectation that the new models will bracket the iPhone 5 with upgraded features in the iPhone 5S and a reduced price point in the iPhone 5C – targeting business/professional users and students/ users, respectively. Accordingly, the two models are likely to target the sweet spot of design, feature set, and price for those market segments.
Teardown preview: Inside the iPhone 5S and iPhone 5C - [Link]
Researchers at Harvard University have demonstrated a new type of loudspeaker transducer which works on a different principle to the conventional moving coil design. It is made up of a thin sheet of transparent rubber sandwiched between two layers of salt water gel. A modulated high voltage signal passed across the two outer gel layers exerts pressure on the rubber membrane, causing it to vibrate and produce sound. The prototype speaker has a frequency response from 20 to 20 kHz.
The effect is produced by the electrical charges carried by ions and not the movement of electrons so strictly speaking this is not an electronic device. The new transducer could be used as an adaptive lens in an optical system or as a window-mounted noise cancellation device. The electrolyte gel is biocompatible so there could also be applications as artificial skin or muscle. [via]
Ionic Gel Speaker - [Link]
TraId – is a Transistor type & pinout identifier:
TraId is a really low cost version of the Part Ninja. It’s made to only identify the pinout and type (NPN/PNP) of a transistor and display the results on eight LEDs. Currently the firmware only handles BJTs but I think FETs should be possible as well.
TraId – Transistor type & pinout identifier - [Link]