Low-Frequency Wien Oscillator - A simple low cost sinusoidal signal generator for the hobbyist's workshop. Battery powered, stripboard-built design. Output 10 Hz to 140 kHz at 2V p-p. Our article also explains the principles of Wien oscillators.

In-Car Laptop PSU - a boost switching regulator design based on the LM2587 that provides an efficient d.c. supply for your laptop computer, from a 12V car supply. Saves you having to purchase a more expensive inverter.

Only suitable for laptops requiring between 14V and 23V. Please check your laptop specifications carefully, e.g. by checking the spec. plate on an existing mains adaptor.

Beat Balance Metal Detector - could this be the ultimate in simplicity? We introduce a new genre of detector that is inexpensive and easy to build. A new hybrid between a traditional BFO and induction balance circuit, using just four CMOS inverters to create a very simple design that has a sensitivity greater than a BFO type, with high levels of immunity to noise and temperature changes.

Experimental Seismograph Logger (2) The second article discusses the software and use of our long term data logger. Free Windows software enables our circuit to run on a compatible PC. Screenshot.

NEW SERIES — PIC n MIX, the new regular series for EPE readers and users (or potential users) of Arizona Microchip PIC microcontrollers. Don't miss out on the revolution that's sweeping through hobby electronics!

Also in this month's magazine: Teach-In 2004 Part 7: moisture detection and radio links. Ingenuity Unlimited (readers' own circuits), TechnoTalk on the possibilities of Smellyvision and Smellyphones! Special feature: coping with lead-free solder - our in-depth investigation tells you what you need to know about the new trends in soldering. How easy is it to solder the lead-free way? Practically Speaking: a beginner's guide to understanding circuit diagram symbols. All this and more in Everyday Practical Electronics magazine.