New The Circles A Gorgeous Round Icon Theme for iPhone & iPad

There is a whole lot of themes available for the iPhone and iPad on the Cydia repository. Unfortunately most of them are actually darn ugly – like really ugly. I don’t know what people are thinking when they pay for these awful themes. As always though, there is one or two which deserve a lot of attention due to the amount of time, effort and craftsmanship put into them. One of my all time favourite Cydia themes is TheCircles.


ipod

However if you’re looking for a free theme which has pixel perfect icon designs, Circles is for you. Jackie Tran (only if his surname was Chan) from Prague, Czech Republic, has released what I personally think is the best free theme available for the iPhone and iPad.

It’s perfectly made for both the iPhone and iPad retina displays with the iPhone icons in the size of 114×114 and the iPad icons in the size of 144×144. The amount of detail put into each icon is really incredible – even the shadows behind the icons are adjusted to make it look like they’re floating on the screen.
iphon

I’ve never been a fan of iOS’ default over-glossy icon design and have always favored matt-like icons – Circles provides this matt look. All default iOS app icons have been changed, including some major apps from the App Store, such as Twitter, Instagram, Facebook and many more. Icons for apps which haven’t been customized still get the circles look by cutting all icons literally into circles.

It’s very hit and miss though because obviously not all app icons will look great cut into circles. If you want to be creative, Jackie even provides the PSD for you to create your own icons so you can get them pixel perfect. Seriously, if you’re looking for the perfect free icon theme for your retina iPhone or iPad – this is it.

Download  TheCircles iPhone & iPad Theme

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Regulators for Battery Powered Systems

Maxim describes various SMPS regulator topologies for battery powered systems. Isolated and non-isolated topologies are covered. 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. [Link]


Switch mode regulators for battery powered systems 1

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Urg Negative Output from Positive Input Voltage

There are some applications, such as double-ended sensors and audio amplifiers that require a negative voltage for operation. With limited space on today’s system boards, creating a dedicated negative supply rail would add to the cost and space of the PCB. Hence, it makes sense to generate the required negative voltage from existing positive supply rails in the system.


One such solution using a traditional synchronous step-down regulator is provided by Texas Instruments in an application note entitled “Creating an Inverting Power Supply Using a Synchronous Step-Down Regulator”1. It shows you how to generate a negative voltage from a positive input voltage to the synchronous buck regulator. [Link]

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LTC3605A – 20V, 5A Synchronous Step-Down Regulator

The LTC®3605A is a high efficiency, monolithic synchronous buck regulator using a phase lockable controlled on-time constant frequency, current mode architecture. PolyPhase operation allows multiple LTC3605A regulators to run out of phase while using minimal input and output capacitance. The operating supply voltage range is from 20V down to 4V, making it suitable for dual, triple or quadruple lithium-ion battery inputs as well as point of load power supply applications from a 12V or 5V rail. [Link]

LTC3605A – 20V, 5A Synchronous Step-Down Regulator

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Mini Block Push-Pull EL84 (6BQ5) Valve Amplifiers

It has been a while since I did anything really crazy in DIY and had it work out far above my expectations. Such is the case for the Mini Blocks. I had a lot of extra parts lying around (really a huge amount of them) and tried to figure out what I could build. Two small chassis about 5 inches by 9 inches by 2 inches (12.5 X 22.5 X 5 cm) were just begging for a project. They are just the right size for lots of things. I first thought of a pair of SET amps.

Mini Block Push-Pull EL84 (6BQ5) Valve Amplifiers

But since I didn’t have any suitable single ended output transformers I nixed that idea. A preamp perhaps could be built on one of the chassis. Since I have many preamplifiers now that didn’t really get the nod either. A pair of small push-pull amplifiers was next on the list. Maybe, but I have so many amps now that it doesn’t make sense either. Since this hobby doesn’t always have to make sense, that is what I built. [Link]

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USB Sound Card

In this article I will discuss my own experiences about designing a USB sound card, which is the USBDAC. DAC is an acronym for Digital-to-Analog Converter because in a sound card, digital data representing the sound is converted into analog voltage that moves the speaker cone.

 Designing a USB Sound Card

My device is loosely based on the PCM2706 reference design. I will not go through the tecnical details but instead concentrate on my own experiences in the design of the device. This is to keep people not familiar with electronics, as well as newcomers to electronics design, interested. You will see that one working product is the result of many failed prototypes. [Link]

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Simple USB Relay – I/O Modules

After the success of small modules USB – I / O converters – PUSBIO with MCP2200 circuit intended for development and small batch production, which we introduced in Article MCP2200 USB module and I / O , and recently introduced software for USB I / O modules , now the company introduces new modules Pandatron with relays and optocouplers. [Link]


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