05 September 2008

The LM3909 was a legendary IC, which the designers (National Semiconductor) modestly described as a "LED Flasher/Oscillator". Its popularity was surely due both to its great simplicity and versatility. It could flash a LED off a wide range of voltages, at a wide range of frequencies. It could also flash LEDs in parallel, could produce a tone in a loudspeaker, trigger a Triac or pulse an incandescent bulb - among other things. Sadly, though, the LM3909 has been discontinued and is now very difficult to find.

03 September 2008

This ultra-high performance model train controller features infrared remote control. We believe it's the best build-it-yourself train controller ever published!

01 September 2008

Back in February 2000 a tender was granted for building a high voltage DC power link between Victoria and Tasmania. It was finally commissioned in April 2006 and now feeds power in both directions between Victoria and Tasmania, depending on demand in those states.

15 August 2008

This versatile LED Strobe & Tachometer can be used to observe and measure the RPM of rotating machinery. It offers three different measurement methods and the readout is via a 2-line LCD module.

11 August 2008

This new amplifier module supersedes both the Plastic Power module described in the April 1996 issue and the Ultra-LD module presented in the March 2000 issue. It produces high power at very low distortion. In fact, as far as we are aware, it is the lowest distortion class-AB amplifier that has ever been published.

06 August 2008

How would you like to try some basic radio astronomy - listening to the bursts of noise originating from the planet Jupiter, or from the Sun? You don't need a lot of fancy equipment to do this, just the simple shortwave receiver described here. It’s hooked up to a basic dipole antenna (which we describe as well) and to the sound card in your PC, so that you can print out "chart recordings" of the noise signals.

05 August 2008

In last month's article, we detailed the construction of the DSP Musicolour. In this month's article, we guide you through the final testing of the DSP Musicolour and give troubleshooting tips. We also explain the operation of the firmware in more detail as well as discussing possible accessories.

16 July 2008

Would you like to connect a stereo amplifier in "bridge mode" in order to deliver double the power to a single loudspeaker system? This simple adaptor allows you to do it, without any modifications being necessary to the power amplifiers themselves.

14 July 2008

Want to connect a professional microphone with balanced outputs to the line input of your PC's soundcard or an MP3 player, for high-quality voice recordings? This microphone preamp circuit lets you do just that. It features a balanced input, has a clipping indicator LED and can be powered from a USB port or from an external DC source.

12 July 2008

This compact device will help you tune almost any musical instrument - acoustic or electronic. It can produce any note on the tempered musical scale (standard pitch) in any of the eight most commonly used octaves, with an accuracy of better than ±0.08% or 1.3 musical cents. The selected note is compared with that from the instrument either by ear or visually by using an eight-LED stroboscopic beat indicator.