It is often said that the oscilloscope is the most useful piece of test gear that the engineer can possess. Over the years ‘scope’ design has improved tremendously; they are now more portable, reliable and offer far better performance than their predecessors. More recently we have seen the introduction of the ‘USB scope’ which digitizes the analogue input signal and displays it on a laptop or PC screen, these offer a good range of features at a reasonable price. For the last 25 years the cost of even a low-spec scope has been beyond the reach of the average electronics enthusiast. During this period many designers with an ambition to own their own scope have risen to the challenge and produced their own design. Many of these home brew scopes appeared in the electronics press in the 1960s and 70s, most of them used valves but in 1975 the fully transistorised (excluding the CRT of course) ‘Elektorscope’ was published in Elektor Electronics.