April 2012

EHT Stick

Specially designed to measure EHT voltages typically found in a CRT monitor or TV, microwave and other high voltage appliances, this special high-voltage adaptor will work with most digital multimeters, allowing measurements of up to 25kV to be taken. For skilled and experienced constructors only, please heed the explicit warnings and cautions published in the article.

High Quality Digital Audio Signal Generator (Part 2)

This sophisticated digital test gear has a backlit LCD display and TOSLINK and coax S/PDIF digital outputs with two analogue audio outputs as well. Generates sine, square, triangle and two sawtooth waveforms, 1Hz to 24kHz.  THD 0.06% (internal DAC) or 0.0006% (ext DAC). Switch between S/PDIF 20-bit and AES/EBU 24-bit modes. Ten memories for storing settings. Many more features too numerous to list here! PICmicro PIC33FJ based. In Part 2 this month, assembly is described. PCB gerber files and source code downloadable from our Library.

Capacitor Leakage Adaptor for DMMs

This project is a “cut down” version of the Digital Capacitor Leakage Meter we described in November 2011’s edition. Instead of using a PICmicro and LCD panel to display the leakage current, this “lite” version connects to your DMM to provide the readout. It measures leakage down to 100 nanoamps, and generates a range of internal test voltages from 10V to 100V. The perfect add-on test equipment for every multimeter owner.

Web Server in a Box FAQs

Here’s a round-up of frequently-asked questions, tips and workarounds for our hugely popular Web Server in A Box project published in December and January. Lots of practical advice will be found in this essential follow-up article!

Also in this month’s issue:

• Techno Talk speculates about a biological replacement for silicon, with news of trials in London’s Imperial College based on bacteria and DNA that won’t cost an arm and a leg.
• Interface – how to build a simple PC-based digital thermometer using a popular sensor.
• Circuit Surgery – analysing the maths behind comparators and oscillators, focussing on the 10A Full Wave Motor Controller of June 2011 issue.
• PIC n MIX – looking at the chipKit Arduino development environment
• Net Work – the Internet column – current trends in image recognition and its implications on Facebook and more; checking road traffic levels around the London Olympics venues thanks to Google, and more.
• Max’s Cool Beans Blog – Max muses about making a diorama in an old TV cabinet!