A metallic foil strain gauge can detect how a test specimen responds when subjected to axial stress. In a previous series, we investigated the Wheatstone-bridge circuit topology and described how strain-gauge elements could be used in the bridge legs. Q: At that point, I asked the question, what is strain, and what are its units? […]
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How physics relates signal integrity, power integrity, and EMC
There came a time when high-speed electronic circuits reached speeds that required engineers to analyze the design for signal integrity (SI), power integrity (PI), and electromagnetic compatibility (EMC). Prior to that time, dedicated experts in separate teams focused primarily on their main specialty. The result: lengthy product review cycles when subsequent teams from these disciplines […]
R&S MXO3 Oscilloscope for EMC measurements: part 1
Rohde & Schwarz recently announced the MXO3, a 1 GHz, 12-bit oscilloscope. The company sent a review unit. In this part, I found that it has some nice features for making EMC measurements, though it could use another. R&S sent me a model MXO38, the eight-channel version with built-in 50 MHz single-channel AWG and two […]
Making sense of test circuits with Kirchhoff’s laws: part 4
We can use a Wheatstone bridge voltage measurement to determine an unknown resistance value. In part 3 of this series, we used Kirchhoff’s voltage law to derive the branch currents and node voltages for an unbalanced Wheatstone bridge with five known, fixed resistors (Figure 1). Now, we propose to replace R5 with a digital multimeter […]
Making sense of test circuits with Kirchhoff’s laws: part 3
Kirchhoff’s voltage law gives us three equations with three unknowns to solve for loop currents in an unbalanced Wheatstone bridge.
Making sense of test circuits with Kirchhoff’s laws: part 2
In part 1 of this series, we looked at ways to simplify resistor networks by identifying series and parallel combinations of resistors. We closed with a look at a version of the Wheatstone bridge, such as the one in Figure 1. Although it has only five resistors, not one of them is in series or […]
Noise generator substitutes for tracking generator
When your spectrum analyzer lacks a tracking generator, you can use a low-cost noise generator to characterize RF components. Here’s how. Low-cost spectrum analyzers often lack tracking generators, preventing you from having a signal source that tracks the analyzer’s frequency sweep. Not having a tracking generator can make some measurements difficult. You can, however, use […]
Making sense of test circuits with Kirchhoff’s laws: part 1
You can avoid solving simultaneous equations in multiple unknowns by identifying series and parallel combinations of resistors. When you buy test instruments, you hope they’ll have the flexibility to provide the necessary stimulus to the device under test (DUT) and acquire and process the response. Occasionally, however, you’ll need to design an external network to […]
Tryout: two low-cost USB inline meters and a load
Despite their limited use for testing wall chargers and power banks, USB inline testers let you compare power sources. In three videos, we take you through their features, and we also try an inline USB electronic load. When testing a USB charger or power bank, you can connect a phone or other device and see […]
Contending with Windows 10’s retirement: part 4
A continuous process of technical architecture modernization can help you prepare for any operating system’s inevitable demise. With the retirement of Windows 10, as described in part 1 of this series, users of the operating system to control test and measurement systems have a choice to make. In part 2, we looked at what steps […]
