In Part 1, we looked at the basic principle and function of the solid-state temperature sensors, as well as the first widely available model, the AD590. Part 2 looks at some application considerations. Q: What are the interface considerations? A: A basic solid-state sensor has a PTAT current-only output. This means that the subsequent circuitry, […]
FAQ
Solid-state temperature sensing, part 1: principles
Temperature is by far the most commonly measured physical parameter in industrial, commercial, and even residential settings. It’s obviously about much more than just “what’s the temperature, so I will know what coat to wear?” Temperature readings are needed to control processes and systems via a negative feedback loop, PID algorithms, and comparators (References 1 […]
Common emitter circuit for analog signal amplification
Today’s microcontrollers are crammed with useful features that have obviated the need for going off chip in order to gain useful functionality. So-called “system-on-chip” or SoC platforms have streamlined product development cycles. They have done this by allowing engineers to spend more time focusing on value-added work and less time on the more mundane glitches […]
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 […]
Demystifying SPICE noise simulation
While I have covered the basics of noise simulation in SPICE before, I thought it was worth revisiting the subject to show some of the confusing results you can sometimes get and how to interpret them. The example I used earlier, a simple opamp based amplifier, didn’t show any unusual noise results but other circuits […]
Analog computing 2.0
Since the late 1970’s, digital technology has dominated the field of computing. Left behind for most applications was the analog computer, a tool that had existed in purely mechanical forms since ancient times (think the Antikythera mechanism, astrolabe or even the humble slide ruler). Before the digital revolution, analog computing offered a lot of promise […]
RS232 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 […]
Practically speaking: 4-20mA current loops
In a world where digital it is all the rage thanks to the promises of concepts such as the Internet of Things, wearables, and augmented reality it’s easy to overlook just how relevant analog technology remains for many industries. Many engineers and technicians can appreciate that from a signals perspective digital signals are but a […]
Photodiode: light sources, the amount of light, and color
I have touched on light sensing methods and the amplification of the signals from them in the past, but at a more fundamental level, how do you choose one? What parameters are important? The answer depends, among other things, on the light source (focused or not), the amount of light and its color. Focused or […]
