Temperature is the most frequently measured real-world variable, and despite its age, thermocouples are still among the most-used temperature sensors. They are used in test and measurement equipment, instrumentation, and even in standard home ovens due to their low cost, reliability, simplicity, and ability to measure into hundreds of degrees. What is a thermocouple and […]
What is a clock and what are its critical parameters (Part 2)?
The performance of a clock function, which includes the crystal and associated circuitry, is defined by parameters which are measured over both the short term and long term. It is also characterized by change in specifications due to temperature variations, aging, and mechanical considerations such as vibration and shock. How is clock performance defined? Both […]
What is a clock and what are its critical parameters (Part 1)?
The “clock” function is a standard part of nearly every electronic system, with very few exceptions. Behind this simple-sounding, commonplace word, there is an array of complexity and subtlety in definition, performance, and design. Clocks are both vital and ubiquitous, so it is worth understanding the different functions they fulfill, they ways they can be […]
How should grounds and commons be connected to each other?
We have already looked briefly at Earth ground (if any), chassis ground, and commons (often misnamed as “grounds”). These do not exist as unrelated connections in a system. The issues related to connecting commons and ground is the subject of countless articles, academic papers, vendor application notes, anecdotes, and even books. There are many rules […]
What are the different “grounds” in electronic design?
The term “ground” is one of the most frequently used words in electronics, and it’s also one of its most-often misused and misunderstood terms. Fortunately, in many cases of misuse, the engineers using it know what it actually being referred to, and are able to translate it internally and so avoid negative consequences. However, there […]
What are some specialized op amp variations?
The operation amplifier – commonly called the op amp – is the key building block of analog circuits. In its basic configuration, it is most often used to amplify a signal, of course. It can also be configured to perform mathematical operations such as implementing multiplication or division of two signals, take a square root, […]
What is Proportional (PID) Control and why is it used? (Part 2)
Part 1 of this FAQ looked at the strengths and weaknesses of basic on/off control as well as the performance improvements that the proportional, integral, and derivative (PID) control algorithm provides. PID analysis PID performance and its setup has been the subject of countless articles, Ph.D. dissertations, tutorials, books, and courses which span qualitative, mostly […]
What is Proportional (PID) Control and why is it used? (Part 1)
Closed-loop control is the foundation of our modern automated world. In simplest terms, this approach applies negative feedback to a system to achieve a desired result. Consider the control of temperature, the most widely measured and controlled real-world physical parameter. If the measured value of this process variable is above the desired setpoint value, we […]