Power Calculations for Pure Sine Waves

Figure 1: For a purely resistive load,
power = voltage * current, with both vectors in phase

Wouldn't it be wonderful if every sine wave we encountered in the real world was pure, with no distortion? It sure would make life easier. Alas, it's pretty much never the case. But in reviewing sinusoidal power calculations, it's best that we begin with the simplest case: a single, pure sinusoidal line voltage and single, pure sinusoidal line current supplying a linear load.

Back to Basics: Probes (Part IV)

Figure 1: An example of
differential probes
measuring from test
point to test point.

In three earlier posts on the basics of oscilloscope probes, we've taken a broad overview approach, looked more deeply at passive probes and inductance effects, and most recently, dug into active probes. Next up is differential probes, a different animal entirely from the foregoing types.

The Realities of Oscilloscope Probes

Figure 1: Teledyne LeCroy's ZS2500

high-impedance active probe

Looking for a good, albeit very expensive, paperweight? Try using an oscilloscope without probes! Probes are often taken for granted but they are one of the most critical elements of the signal chain in any test scenario.