A plus times a plus is a plus. A plus times a minus is a minus. A minus times a plus is a minus. A minus times a minus is a plus. Because none of these operations results in a negative product, we must confront the hard reality that the square root of a negative […]
FAQ
Precision and accuracy in oscilloscopes
The precision and accuracy of voltage measurements made with a digital scope are affected by the speed at which samples are taken, i.e. the sampling rate, and sampling depth or bit depth. Bit depth is just the number of bits of information in each sample, and it directly corresponds to the resolution of each sample. […]
Using the scope integration function to determine energy use
Integrals come in handy in measuring power consumption when that consumption is intermittent or corresponds to a dissipation vs. time function that is irregularly shaped. The classic example is that of a controller that wakes up every second or so. You can, of course, use single-shot capture to get the current waveform when the controller […]
Why the sky is blue: LiDAR puts a focus on measuring Raleigh scattering
Most people assume the sky is blue because through a process of refraction we see the higher-frequency, shorter-wavelength end of the spectrum. This explanation is incorrect. For one thing, if the entire sky is blue, what happened to the rest of the spectrum? It’s complicated. In actuality, the blue appearance of the sky and yellow […]
Dealing with noise in electronic circuits
Where there is matter, there is the potential for free electrons, and unless the temperature is absolute zero, these electrons exhibit random motion. Thus the basis for noise in electronic circuits. In metals such as copper, the number of these free electrons is large and their motion appears to be independent and truly random. Electronics […]
Understanding basic oscilloscope uses
The dominant oscilloscope type today is digital. A relatively small number of analog oscilloscopes are still made for educational purposes and low-end DIY kits. The digital revolution in oscilloscope design, initiated by Walter LeCroy over 50 years ago, made possible vast new capabilities and features. Still, it is worthwhile for perspective to look back at […]
Budget-priced transistor testing
The field-effect transistor (FET) in one form or another has largely superseded the earlier bipolar junction transistor (BJT). Both can do amplification, oscillation, and switching, but the methods in getting there are quite different as are the input and output impedances. First, by way of background, we’ll look back at the BJT. It contains three […]
Measuring energy without getting fooled
James Prescott Joule, in formulating what is now known as Joule’s Law, found that various forms of energy such as mechanical, electrical and heat are essentially identical and can be changed one into the other. His work formed the theoretical basis for the First Law of Thermodynamics. Joule further investigated the phenomenon of magnetostriction. He […]
Negative resistance: meaning and measurement
It is a fact, verified in theory and by experiment, that no material can conduct electric current with greater efficiency than an ideal conductor having zero resistance. How, then, can the term “negative resistance” have meaning in the real world? First, it is possible to get negative resistance readings on a DVM. If this happens, they […]
Measuring with spectrum analyzers
Modern bench-type and even hand-held oscilloscopes have spectrum analysis capability, providing great added versatility. They can view in rapid succession (or even simultaneously in split-screen format in a mixed-domain instrument) time domain and frequency domain displays of the same signal. Fourier theory tells us that any signal or function in the time domain can be […]
