03 September 2010

Boaties like to have access to radio, music and on larger vessels, video. Whether they are cranking the music up on the long run to fish the continental shelf, relaxing at anchor or keeping track of weather reports, they want performance and state-of-the-art gear.

25 August 2010

Got a bunch of old electrolytic capacitors you'd like to use . . . but don't know if they are any good? Or do you need to re-form the electrolytics in an old valve amplifier or vintage radio set? This Electrolytic Capacitor Reformer and Tester will do the job for you, at any of 11 different standard voltages from 10V to 630V.

19 August 2010

This signal generator can deliver a 14-bit arbitrary waveform at 250 megasamples per second, a sine or square wave up to 50MHz or a triangle wave up to 10MHz. It can modulate the amplitude, frequency or phase by another generated or external waveform. It also does Pulse Width Modulation (PWM), Frequency Shift Keying (FSK) and more.

17 August 2010

Most readers would know that you can obtain small ultrasonic cleaners for jewellery and similar small items. So why not a much larger version? It would be great for cleaning automotive and other mechanical parts, fabrics which cannot be machine washed, ornate bric-a-brac and a host of other hard-to-clean items.

15 August 2010

This remote-controlled digital timer has a bright 20mm-high 7-segment red LED display & can count up or down from one second to 100 hours in 1-second steps. Its timing period can either be set and controlled using the remote control or it can be automatically controlled via external trigger/reset inputs. An internal relay and buzzer activate when the unit times out.

13 August 2010

Thirty years ago, any hifi enthusiast worthy of the name would have hocked his soul for a Quad hifi system with electrostatic loudspeakers. But how does the Quad gear of that era stack up against modern hifi gear?

11 August 2010

It is often said that solar power plants can't 'do baseload' - that they only provide power when the sun shines. Not so: Richard Keech and Matthew Wright* explain how solar thermal plants work and how the Spanish now get solar power around the clock using advances in thermal storage.

07 August 2010

Here's a 12-32V 30A speed controller that's easy to build. It's available in two versions – reversible and non-reversible – and features soft start, relay switching of motor direction and PWM speed control.

05 August 2010

Interesting circuit ideas which we have checked but not built and tested. Contributions from readers are welcome and will be paid for at standard rates.

03 August 2010