October 2026

Buying Second-Hand Speakers

If you’re on the lookout for some loudspeakers without wanting to pay an inflated ‘new’ price, this article gives you some handy hints and tips about what to look out for. If you have an eagle-eye, some real bargains can be had, so this feature will hopefully give you some useful pointers when browsing those surplus stalls.

Power Electronics
Part 7: Resonant Converters & Soft Switching

Continuing this advanced primer on power circuitry and techniques, this installment describes more principles surrounding higher switching frequencies and how to overcome switching losses.

DCC Decoder for Model Locomotives

Digital command control (DCC) has been around for several decades in the model railway world. Our project is right up to date and utilises a PIC microcontroller circuit in a sub-miniature circuit to provide realistic control of your N and HO/OO scale locomotives. This article also includes a DCC glossary of terms. We will follow up with a DCC Base Station project to enable you to build a complete command and control system for your layout.

Ducted Heat Transfer Controller
(Part 1)

The purpose of this design is to control a mains-powered fan to transfer heat between rooms using ducts. The controller can be used manually, automatically or based on a timer. Especially useful if one room is a primary source of heat, such as a wood-burning stove, this design offers fan-forced heat distribution around residential properties, maximising the output of the stove. It can also be configured as a fire alarm. The circuitry and principles of operation are described this month, with construction following in Part 2.

Rigol DHO924S Digital Oscilloscope and DM858 DMM review

The new compact DHO924S digital storage oscilloscope is brimming with features, and we couldn’t wait to try one out. This review offers highlights as well as a quick look at the DM858 digital multimeter.

Net Work

Our occasional column reveals some murky misnomers in the field of “21V” Li-Ion power tool batteries that have become very popular recently. Also described are trends in Chinese mass production using 3D printing, latest news on the forthcoming ‘Temu tax’ on low-value imports and some of the latest developments in the electric vehicle market that are heading our way.

Home Assistant with a Raspberry Pi
(Part 2)

Having set up our custom Home Automation system, we examine some advanced features that can utilise it, including cameras, custom dashboards, IR remote controllers, remote phone or tablet access and more.

Audio Out
The RetroTech UK exhibition and radio rallies, Part 2.

More vintage TV cameras, broadcast  equipment and audio gear are unearthed at the RetroTech UK rally.

Circuit Surgery

Our in-house surgeon suggests a transistor-level model of the 555 timer IC in LTspice. Demo circuits include taking water conductivity measurements using the classic timer.

The Fox Report

Barry Fox is given an insight into the latest state of the art in humanoid – and canine – robotics that are emerging from China.

Techno Talk with Max the Magnificent

Max muses over the way AI is rapidly being adopted in the areas of web design and testing, simulating and viewing web pages and interacting with chatbots just as a human would.

Weird & Wonderful Arduino projects
Part 22: Implementing the Game of Life, Seeds and Brian’s Brain.

Max also works on the 7-segment VFD-based Chronological Contraption.

Next month:

Digital Preamplifier & Crossover; ‘Earth’ Radio Receiver; RGB LED Christmas Star