In part 1 of this two-part guide, we talked about the trade-offs you need to make when selecting the type of capacitor that will be the best fit for your application and the basics of trimmer capacitor design including dielectric material options. This second post focuses more on the details of trimmer capacitor specs and how to determine what's right for your application.
As you already know, capacitors are essential circuit elements for storing and suppling charge on demand. For inductors and resistors, capacitors act as the building blocks of passive circuits and the supporting components for active circuits. While a wide range of fixed-value capacitors are used in most electrical circuits, it is sometimes preferable, or necessary, to use a component with a variable capacitance range.
Today, a wide variety of capacitors with a range of features are available, which can make it difficult for circuit designers and electrical engineers to determine the best fit for their application. To add to the confusion, there is somewhat of a misconception today that some capacitors, such as tantalum and Class II MLCCs, are interchangeable. But this is not always the case. Each capacitor type has distinct advantages and disadvantages that are important to understand to ensure you choose the right technology to best meet the needs of your specific application requirements. This post provides a brief overview of these two capacitor types as well as a variety of factors to consider when making your capacitor selection.
As RF and microwave systems require higher performance in a small footprint, designers and engineers need to get more out of every component, including capacitors. To meet these demands, Knowles Precision Devices has expanded its line of single-layer vertical electrode (V Series) capacitors to include the 100nF V80 Bypass Capacitor. The V80 is a revolutionary development for capacitors as it is the first SLC to feature an operating voltage of 50V in .084” x .042” package. The closest competitor product at this size is only rated for 16V.
With our new expanded range of enhanced safety-certified multilayer ceramic capacitors (MLCCs), Knowles Precision Devices now offers a unique combination of capability and safety certification for electronic device applications. These new surface-mount MLCCs comply with international UL60384-14 and EN60384-14 specifications and can be used instead of leaded film capacitors in AC-DC power supplies where a lightning strike or other voltage transients represent a threat to the electronic equipment.
In an ideal world, capacitors could be designed in a way where they would exhibit no resistance. However, this is physically impossible to achieve as there will always be some type of internal resistance in a capacitor that appears in series with the capacitance of the device. Known as equivalent series resistance (ESR), the level of this resistance will vary across capacitors depending on a variety of factors including the dielectric materials used, frequency of the application, leakage, and quality and reliability of the capacitor. The two graphs in Figure 1 show an example of how ESR can change as frequency increases across various capacitances on two different classes of ceramic dielectrics.
In electric vehicle (EV) applications, filter capacitors are a special type of component commonly used as input and output capacitors. Also known as noise suppression or electromagnetic interference (EMI) filters, these particular capacitors act to remove noise and other unwanted signals on the line. On the high voltage alternating current (AC) side of a system, the capacitors often provide EMI filtering, whereas on the direct current (DC) side of a subsystem, they serve to smooth ripple components of the AC and filter out noise.
In our last article about electric vehicles (EV), we talked about using DC link capacitors as an intermediary buffer in power converters. Today’s topic covers another useful power module component – the snubber capacitor. Snubbers are energy-absorbing circuits used to protect electronics from voltage spikes and transients caused by turning a switch from the On to Off state. Opening a switch intrinsically induces a high voltage across the device, and the snubber provides an alternate flow path for the excess energy to be absorbed by the snubber capacitor and dissipated by a resister or other load.
To provide a better understanding of build-to-print in general and the breadth of our offerings, as well as how our thin-film technology can benefit your applications, we’ve put together a Build-to-Print Basics series. Part 4 provides an overview of our process and the topics our applications engineers review with clients to kick-off any build-to-print project.
Many circuits in broadband applications require the coupling of RF signals, which can be a complicated process since it involves removing the DC component to allow only the high-frequency AC component to pass or bypass. Removing the AC component from a DC line is done by placing a coupling capacitor in series with the path the signal takes.