November 2011

Digital Capacitance Leakage Meter

This PICmicro powered test gear lets you perform a leakage current test on almost any type of capacitor, including ceramic, polyster, mica, tantalum or aluminium electrolytics.  Seven standard test voltages are available from 10V to 100V allowing most capacitors to be tested at their rated voltage. Leakage currents from 100nA to almost 10mA can also be tested.  Informative LCD alphanumeric display all in a self-contained unit. Capacitor Leakage Current Guide Table also included.

This high voltage project is intended for experienced constructors only.

Using a wideband O2 Sensor in your car (1)

This very advanced special feature describes a Wideband Controller originally intended for a Bosch wideband oxygen sensor along with our Sensor Display (Oct. 2011)  to measure air/ fuel mixtures over a broad range.  Helps with precise engine tuning and can either be permanently installed or used as a temporary monitor hooked onto the exhaust. An ideal project for the advanced automotive tuning enthusiast.

One-of-Nine Switch Indicator

Originally designed as a “track-in-use” indicator for model railway layouts, this one-of-nine indicator can be used with any selector switch or reed relay system having up to nine positions. Cleverly provides a single-digit seven segment display to indicate the selected position.

Optional remote display “extender board” can be located many metres away if needed. Ideal for model railroad turntable positioning or track selection, but it has many other uses as well. Easy to build, based on a discrete CMOS logic circuit.

Stereo DAC Sound System for DVD Players (3)

This versatile ultra-high quality design is a 24bit 96kHz-capable stereo DAC that provides sound quality equal to the best high-end CD players.  It’s the ideal accessory for discerning audio enthusiasts who enjoy listening to their CDs on DVD players but are disappointed by the myriad of hums, buzzes and distortion that their DVD player can introduce on the sound.

The Stereo DAC is rack-mounted, has a toroidal mains transformer and features PCBs for the DAC, switch panel and power supply. An ATMEL  MCU is used in this project. Part 3 this month covers the final assembly details and remote control operation.

Also in this issue

• Techno Talk goes mining for rare earth elements, examining the future impact on electronics that their diminishing supply may have;
• Practically Speaking examines type numbers used on semiconductors;
• Circuit Surgery – our in-house “surgeon” homes in on the ins and outs of impedance. Don’t miss this valuable educational article;
• Max’s Cool Beans – more musings from Max the Magnificent, who eyeballs the iPad and hasn’t looked back;
• Net Work – the Internet column – updates you on the latest in the tablet market, plus some considerations for securing your mobile data.