digisplay - p.c. board for the

2-32 — elektor february 1980 digisplay p.c. board for the It was probably the simplicity of the circuit"s design which helped it to score such high points. It extends the uses of an oscilloscope considerably and at a relatively low cost. Usually one can only observe several TTL levels at once by taking notes at the same time. If the levels are static there is no problem, but when levels vary it becomes more difficult. The digisplay can be used to observe static levels as well as slowly changing ones (for signals which change rapidly, other methods will have to be sought), so that an overall picture of everything happening in the circuit is obtained at a glance. The lay-out The original circuit (as published in the Summer Circuits issue) has been modified slightly, as shown in figure 1. The oscillator around N1 and N2, in particular, needed some attention. The result is an oscillator which starts up without any trouble at all — unlike the., older version. The complete circuit w...