15 November 2008

This handy circuit can be used as a speed controller for a 12V motor rated up to 5A (continuous) or as a dimmer for a 12V halogen or standard incandescent lamp rated up to 50W. It varies the power to the load (motor or lamp) using pulse width modulation (PWM) at a pulse frequency of around 220Hz.

27 October 2008

This LCD USB Clock connects to your PC's USB port. It synchronises its time with your PC - and ultimately an internet time server - when your PC is on to maintain accurate time-keeping. It can also operate on its own using battery back-up and has user-selectable display modes.

23 October 2008

This automatic timer has a wide range of applications whereby a timing cycle is initiated in response to a trigger signal. There are quite a few uses for it in a car or you could use it on a model railway layout, in a home security system or whatever.

17 October 2008

Need to measure small signals at radio frequencies? Here is a low-cost digital level and power meter which will allow you to measure RF signals from below 50kHz to above 500MHz. As well as indicating the signal level in volts and dBV, it also shows the corresponding power level (into 50 ohms) in both milliwatts and dBm.

09 October 2008

Last month we presented the circuit, specifications and parts list for our new high-performance Railpower IV model train controller. Now it's time for the construction details - and we show you how to set it up for best performance.

11 September 2008

Last month, we published the circuit of our new LED Strobe & Tachometer and showed how to build the main unit and the strobe light. This month, we describe the assembly of the optional Photo-Interruptor and IR Reflector Amplifier boards. We also describe how the unit is used.

10 September 2008

With a small and low-cost add-on PC board, the DSP Musicolour can be operated via an infrared remote control - very handy if you want to use it in hard-to-reach places.

09 September 2008

Last month, we introduced our new Ultra-LD Mk.2 200W Amplifier module and described the circuit. This month, we give the assembly details and describe a suitable power supply.

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!