Ronald writes –

The oscilloscope is still one of the most important measurement tools of the electronic engineer. With the advent of the often very reasonably priced USB scopes, such an instrument is now within reach of every body. Twenty five years ago that was quite a different story. A (good) oscilloscope was then a very expensive instrument available only to a happy few. As a result many electronics hobbyist made their own scope. The popular electronics magazines in the sixties and seventies were full of scope designs almost always based on vacuum tubes. This period was closed in 1975 when the Dutch electronics magazine Elektuur (in the rest of the world known as Elektor) published their fully transistorised “Elektorscoop”. Despite all this, the purchase of the expensive cathode ray tube and Special high voltage transformer remained too expensive for many people.

In an effort to lower the price for a scope even further, Elektuur published in 1978 the “Videoscope”. The Videoscope sampled the analog input signal and stored the samples in a bucket brigade (CCD) memory. Next the data in the CCD was converted into an ordinary (black and white) video signal which could be displayed on an ordinary TV. In order to view the signal in the normal way the TV had to be put on his side, but nobody minded that. All in all it was still a rather complex design comprising a few dozen of ICs and several printed circuit boards.

These days this obviously can be done much simpler…

A poorman’s oscilloscope – Link.