Electric motors – from tiny ones which advance a sheet of paper, to huge ones which power industrial machinery — are so common that we may not give them adequate consideration. Motors have a complex history and genealogy, which can be confusing to newcomers, Figure 1. Each motor subtype has unique characteristics which make it […]
Radio receiver architectures, Part 1—TRF and Superhet
A transmitter has much-less challenging task than the receiver. The former operates on a higher-level, known signal in a known setting, while the latter must find and decode a largely unknown signal corrupted by internal and external noise, interference from other signals, distortion, low signal levels, and constantly changing parameters. This FAQ looks at the […]
RS-232 and Related Standards, Part 2
Part 1 looked at the basics of RS-232. This part continues that examination, along with some extensions to the standard and test issues. Q: What are some of the issues associated with RS-232 and its performance? A: The standard allows for many user choices in how the DTE and DCE are configured: number of data […]
RS-232 and related standards, Part 1
High-speed, high-performance “just plug and go” wired-communications interfaces such as Ethernet and USB are in wide use. In contrast, the technically ancient RS-232 standard and related standards seem like antique museum pieces with no design-in interest. However, that is a simplistic view of the reality. Although not necessarily the first choice or obvious choice in […]
Solenoids and relays, Part 2
Part 1 looked at the solenoid, an electromechanical component which translates applied current into linear motion. The design of the electromechanical relay uses a coil and current drive (or a voltage source) just as with the solenoid. However, the function of the relay is quite different. Despite the availability of alternatives for some applications such […]
Solenoids and relays, Part 1
Just hearing the words “solenoid” and “relay” may conjure up visions of an ancient electromechanical word, now largely replaced by all-electronic devices, smart motors, and more. That almost makes sense, as these two components in various forms have been with us for over 150 years. But don’t be fooled: both are still vital devices, and […]
Fuses for power protection, Part 2
Part 1 of this FAQ explained fuse basics. Although fuses are simple in principle, selecting the most suitable fuse for the application is more complicated than it may seem at first. Q: What are the key questions to ask when selecting a fuse? A: These are just a few of the considerations: What is the […]
Fuses for power protection, Part 1
Fuses are the oldest and easiest-to-understand circuit-protection components, with several common schematic representations, Figure 1. The function of the fuse is simple and clear: in the case of an overcurrent condition, the fuse “opens” (or blows, in common parlance) which thus stops the flow of current. Despite their simplicity, fuses have subtleties and considerations which […]
Current feedback amplifiers, Part 2
Part 1 of this FAQ look at the operation of the CFB op amp and compared it to the VFB op amp. Part 2 continues the discussion of these two op amp topologies and their characteristics. Q: How do you choose between VFB versus CFB? A: Today’s CFB and VFB amplifiers have comparable performance, but […]
Eye and Constellation Diagrams, Pt 2
Part 1 looked at the eye diagram, a simple yet powerful visual tool which reveals many specifics about the quality of a recovered bit stream. Part 2 looks at the constellation diagram, another powerful visual tool which is used to show the signal space of complex encoding schemes and relationship among the symbols. Q: Why […]
