The spectrum analyzer is a member of the oscilloscope family. An electrical signal is fed, by means of a BNC cable or probe, into an input port on the front panel, and its graphic image appears on the LCD screen. But rather than the oscilloscope’s familiar time domain graph, in which amplitude in volts is […]
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Basics of voltage doubler circuits
Voltage can be doubled (and therefore multiplied by any power of two using cascading devices) through purely electronic means without resorting to a transformer. Voltage-current ratios apply, so doubling is not a question of getting free electrical energy that did not previously exist. Doubling the voltage and thus reducing the current available at the output […]
Basics of troubleshooting power supplies
When a piece of equipment turns up completely dead, one of the first things to look at is the power supply. If using an oscilloscope for this sort of troubleshooting, it should be a hand-held, battery-powered instrument isolated from ground, at least at the outset. The reason is there may be internal voltages that are […]
COVID-19 and climate change
A single coronavirus particle mutated and survived the transition from animal carrier to human victim, and so far with verified U.S. cases exceeding one million, there is no known therapy or protective vaccine. An unexpected consequence of mediation efforts is that for the first time in generations, Los Angeles and other urban areas have blue […]
Difference between phase distortion, phase modulation, and frequency modulation
The concepts of signal phase modulation and signal frequency modulation, and the difference between them, are often a source of confusion. Ditto for the related idea of phase distortion. Here, we’ll try to clarify things. To understand phase distortion, recall that any waveform can be considered to be a sum of sine waves of different […]
Difference between signal jitter and frequency modulation
Jitter and frequency modulation both involve a change in the frequency of an underlying signal. It’s worth investigating how the two phenomenon differ. Jitter is usually defined as an undesired deviation in timing of a signal from its original periodicity. It can take the form of variations in phase, period, or duty cycle. And jitter […]
Basics of amplitude distortion
Amplitude distortion is the unintended modification of a signal, typically while undergoing amplification. Amplitude modulation, in contrast, is the intended modification of a carrier wave in response to a varying audio, video or other information-bearing signal. Sources of amplitude distortion include noise and interference, but the main source is non-linear amplification. Amplitude distortion can include […]
Overview of electrical measuring instruments, Part 3
In recent columns, we’ve given a quick review of some basic instrumentation common to most engineering work benches. Here are a few more instruments found in many engineering labs. Signal generator Signal Generator is a generic term describing various instruments, all sharing a single rationale, which is that a device under test (DUT) requires a […]
More dangerous than the virus? Converting manual resuscitators to ventilators
The shortage of respiratory ventilators in the face of the Covid-19 pandemic has led to numerous efforts aimed at turning hand-operated plastic pouches called bag-valve resuscitators into makeshift ventilators. The resuscitators, also called Ambu bags, are generally on-hand in large quantities. They are designed to be operated by hand, by trained technicians, to inflate patient […]
Overview of electrical measuring instruments – Part 1
Here’s a quick review of some basic instrumentation common to most engineering work benches. Ammeter The ammeter is the basis for many other electrical measuring instruments. Whether you are measuring volts or ohms, essentially inside the instrument you are measuring current. Measurement of current in a circuit is somewhat problematic because all the electrical energy […]