Capacitors serve many crucial functions in power electronic circuits. Their ability to store electric charge makes them essential components for regulating and smoothing power flow. 

Many of these capacitors are standard fare, but a few play highly specialized, functional roles. To meet application-specific demands, these capacitors must be selected carefully based on function, size, and interoperability. 

Before jumping into a discussion on ceramic coaxial resonators, it is important to understand what a resonator is and how these electrical components work. In general, a resonator is an essential component for constructing a bandpass filter since the resonator is what will allow specified frequencies, or bands of frequencies, to pass through the filter as shown in Figure 1.

Digital and connected healthcare methods are getting better and better at harnessing the full potential of today’s advanced medical technologies and popular consumer devices. This combination is evolving standard healthcare delivery for the digital age. While these technologies still pose privacy, security and access challenges, they’ve made significant strides. The vision of a less hospital-centric, and more patient-centric, system is starting to crystallize.

In 2023, our experts continued their commitment to teaching engineering basics and sharing their insights into the latest industry trends and challenges. Hopefully, you’ve found our lessons and insights valuable. We appreciate that you turn to us to learn about the industry, and we take your readership seriously.

As a fundamental component of circuit design, equivalent series resistance (ESR) is the measurement of all the non-ideal electrical resistances in series with a capacitor. When current flows through a multilayer ceramic capacitor (MLCC) due to application of alternating voltage, heat is generated in the MLCC due to the losses, specifically ESR. As a result, this self-heating can cause various performance and reliability issues in the circuits of today’s more complex and smaller electronic systems.

The power electronic systems in an electric vehicle (EV) feature a wide variety of capacitors. From DC-link capacitors to safety capacitors and snubber capacitors, these components play a critical role in stabilizing and safeguarding the electronics from factors like voltage spikes and electromagnetic interference (EMI). Here, we’ll focus on the capacitors used in the EV traction inverter.  

With the rising prevalence of cardiovascular, orthopedic, and other chronic conditions, and an increase in the number of patients needing care, the demand for implantable medical devices continues to increase. 

Quality factor, or Q factor, is a common shorthand figure of merit (FOM) for RF filters. It’s typically expressed as the ratio of stored versus lost energy per oscillation cycle. Steepness of skirts, selectivity, and insertion loss are all specifications that can be described in terms of Q factor. While this FOM feels ubiquitous in RF, truly understanding how Q factor is determined and how it relates to other specifications is a complex endeavor because it’s contextual. 

There are hundreds of filter applications operating across a wide range of frequencies, which presents a challenge for filter designers since most filter designs don't inherently operate across these wide ranges. Size, weight, power, and cost (SWaP-C) are also important considerations, so simply adding more filters to address different frequency ranges is not an attractive solution. There is, however, an alternative way of designing filters: combining filter technologies to meet the specific frequency, bandwidth, and size requirements of your application.

Welcome to the Capacitor Fundamentals Series, where we teach you about the ins and outs of chips capacitors – their properties, product classifications, test standards, and use cases – in order to help you make informed decisions about the right capacitors for your specific applications. After describing soldering for capacitors in our previous article, let’s discuss common formulas and calculations for capacitors.