The Best Capacitor Circuit Simulator for PCB Design

Zachariah Peterson
|  Created: March 22, 2021

A capacitor is a fundamental element in integrated circuits and in PCB design, and it’s hard to think of a circuit that doesn’t contain at least one capacitor. A capacitor’s behavior and interaction with other components in a circuit generally needs to be simulated to ensure the design will operate as intended. Capacitors can provide filtering, blocking, and power stability behavior depending on their use in a circuit, and a capacitor circuit simulator can help you verify the safety and efficacy of your design.

The best PCB design software will include a SPICE package that lets you run transient analysis for your capacitor RC circuits, as well as other common circuits. Altium Designer provides these circuit simulation tools and much more in a single application, making it easy to create and perform capacitor circuit simulations. Once you’ve verified your circuit design, you’ll have everything you need to create a high-quality PCB layout with the industry’s best ECAD tools.


A unified PCB design application with a powerful SPICE simulation engine and a complete set of CAD tools for professional designers.

There are three fundamental linear circuit elements that can be used to describe a broad range of behavior in PCB design: the resistor, capacitor, and inductor. These circuit elements can be combined in creative ways to produce all sorts of useful functions in an electronic device, but simulation tools are needed to ensure designs operate the way a designer intends. Capacitor circuits, in particular an RC circuit, see broad use and are fundamental for describing a range of behavior in electronics design.

Once you create your capacitor circuit design, you’ll need a capacitor circuit simulator to verify the design and ensure it functions as intended. These simulation programs are based on SPICE engines, which allow a designer to run a circuit simulation before creating a physical PCB layout. There are a few important metrics that can be quickly calculated in a capacitor circuit simulation as long as you use the right electronics design software.

Capacitor Circuit Simulation Methods

Circuit simulation programs based on SPICE operate by solving differential equations using an iterative algorithm. These can be performed in the frequency domain or in the time domain, and the best circuit design tools will let you perform additional analysis to help you understand your circuits. In a capacitor simulation, there are some specific points that should be calculated:

  • Transient analysis to determine the RC time constant
  • Transfer function analysis to understand filtering behavior
  • Impedance calculations to ensure matching in high speed/high frequency circuits

PCB design applications like Altium Designer will include a complete set of circuit design tools in a schematic editor, allowing designers to perform any type of circuit simulation, including capacitor simulations. It’s easy to build a larger system around your capacitor circuit with a voltage or current source, and you can calculate important electrical values like current and impedance with Altium Designer’s intuitive interface.

Purpose of a Capacitor Circuit Simulation

A capacitor circuit simulation is intended to examine the transient response and frequency domain response of a capacitor circuit. While the time constant and transfer function are normally the most important points to calculate, there are other important quantities that can be determined. Two important values are the time-domain current from AC analysis, as well as impedance in the frequency domain. Iterating through these different circuit parameters in multiple capacitor circuit simulations can help you optimize a circuit to have the desired response.

Capacitor circuit simulation

Altium Designer’s integrated circuit simulation tools can help you optimize a circuit to have a specific passband in the transfer function.

More Complex Capacitor Circuit Simulations

Real capacitors are simple and they operate just as we learn in electronics classes. The reality is that capacitor circuits have parasitics, particularly series inductance and series resistance on the component leads. This means that, in order to model a real capacitor, there needs to be an inductor and resistor in series with your capacitor to create an accurate capacitor simulation.

Capacitor circuit simulation

Example schematic for a capacitor circuit simulation.

Capacitor circuits, such as RC circuits, can be combined with resistors and inductors in other ways to create complex filters, amplifiers, and impedance matching networks. These circuits need to be examined with the same tools as a basic capacitor circuit to ensure the design will provide the desired transient response. This is very important in AC analysis of analog components, such as RF filters and antennas, and even transmission lines for high frequency circuits.

Capacitor Circuit Simulation Process

To run a capacitor circuit simulation, simply set up your circuit with a voltage or current source from your simulation libraries, and select the type of analysis you want to perform. The two most common analyses are transient analysis and frequency sweeps to calculate a transfer function, but other important analyses like pole-zero analysis and noise analysis can be performed in Altium Designer. The next time you need to design circuits and perform a circuit simulation, use Altium Designer’s integrated design tools.

Capacitor circuit simulation

Altium Designer’s integrated circuit simulation tools can quickly calculate the transfer function for a complicated filter, amplifier, or other linear circuit.

Instantly Capture Your Capacitor Circuits in Your PCB Layout With Altium Designer

Once you’ve finished your circuit schematics, it’s time to create a PCB layout for your system. Altium Designer’s integrated PCB design environment doesn’t separate schematic capture and PCB layout tools into different applications. Instead, you can remain productive and quickly capture your circuits in a blank circuit board when you use Altium Designer’s integrated set of PCB design tools.

Altium Designer is known for providing the industry’s most powerful PCB layout and routing features alongside a world-class schematic editor and SPICE simulator. It’s never been easier to layout your components with ultra-accurate CAD tools, and you can quickly place traces in your PCB layout with the best routing tools.

Manufacture a Real Product With Altium Designer

Once you’ve finished your PCB layout, it’s time to prepare your board for manufacturing. In addition to the industry’s best design tools, Altium Designer can instantly generate deliverables for manufacturers in standard file formats. No other PCB design software application makes it this easy to create a high-quality PCB layout and have it produced at scale.

Capacitor circuit simulation

Altium Designer provides a comprehensive set of PCB design and circuit simulation tools.

Other PCB design applications make SPICE simulations difficult, or they don’t include the basic tools needed for capacitor circuit simulations. Instead, use the only application with the industry’s best PCB layout and routing utilities, integrated simulation features, and a comprehensive rules-driven evaluation engine. Altium Designer gives you these important circuit design tools alongside the industry’s most powerful PCB layout tools in a single program.

Altium Designer on Altium 365 delivers unprecedented integration to the electronics industry until now relegated to the world of software development, allowing designers to work from home and reach unprecedented levels of efficiency.

We have only scratched the surface of what is possible to do with Altium Designer on Altium 365. You can check theproduct page for a more in-depth feature description or one of theOn-Demand Webinars.

About Author

About Author

Zachariah Peterson has an extensive technical background in academia and industry. He currently provides research, design, and marketing services to companies in the electronics industry. Prior to working in the PCB industry, he taught at Portland State University and conducted research on random laser theory, materials, and stability. His background in scientific research spans topics in nanoparticle lasers, electronic and optoelectronic semiconductor devices, environmental sensors, and stochastics. His work has been published in over a dozen peer-reviewed journals and conference proceedings, and he has written 1000+ technical blogs on PCB design for a number of companies. He is a member of IEEE Photonics Society, IEEE Electronics Packaging Society, and the American Physical Society, and he currently serves on the INCITS Quantum Computing Technical Advisory Committee.

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