MEASURING INSTRUMENTS
Oscilloscope: signals over time
From V/div and time/div to triggering and safe differential bus measurements.
The principle
An oscilloscope samples voltage and plots it against time. V/div sets the vertical scale; time/div sets the horizontal scale. A trigger begins acquisitions at a recognizable edge. Vpp is maximum minus minimum; a period T gives frequency f = 1/T. Bandwidth, sample rate and probe attenuation affect accuracy. Unlike a multimeter, a scope reveals edges, noise, overshoot and timing.
An example
Switch between sine and square waves. Adjust the scales and trigger level. The simulation displays 2 Vpp and a 1 kHz source with a 1 ms period. For a differential bus use a suitable differential probe or safely referenced channels and a mathematical difference.
Important
The ground clip on many bench scopes is connected to protective earth. Never attach it to an arbitrary bus wire or mains conductor. Use appropriately rated differential or isolated equipment for floating or hazardous signals. Never defeat protective earth.