“Passives” in general within the electronics community are devices that do not drive or transmit power or signals. Passive Sensors do not control electricity directly and do not require external power sources to accomplish control of an electrical signal. Examples of passive components are resistors (R), capacitors (C), inductors (L), transformers, antennas, potentiometers (variable resistors), […]
FAQ
Mutual inductance & transformers: when EMF becomes EMI
Mutual inductance is superbly demonstrated in a transformer. Transformers are made up of two wire coils placed close each other such that current running in one coil can induce a voltage in the other coil without the coils touching. Power can be transferred without a metal connection with a transformer, and transformers can be […]
Phase Locked Loop: A fundamental building block in wireless technology
A phase-lock(ed) loop (PLL) is a fundamental building block in wireless, radio frequency (RF), and telecommunication technologies. PLLs use a negative feedback circuit to match the phase of the frequency of another signal. PLLs synchronize the phase of the PLL’s output to the input signal’s frequency by tweaking the output of a voltage-driven oscillator; the […]
Pulse Width Modulation (PWM): what is it and how does it work?
Digital signals have two positions: on or off, interpreted in shorthand as 1 or 0. Analog signals, on the other hand, can be on, off, half-way, two-thirds the way to on, and an infinite number of positions between 0 and 1 either approaching 1 or descending down to zero. The two are handled very differently […]
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, […]
Working with op amps: tying down floating pins
Operational amplifiers are used in many configurations and with many variations on specifications, depending upon the application. However, an IC package of operational amplifiers will often come with several in a package (e.g., a “quad pack” will have four op amps). If you have leftover, unused op amps on the same chip, the unused ones […]
