Free Online Circuit Design Tools Now Available


This item would normally be placed in my RF Shorts section, but due to its usefulness for a wide range of readers, I wanted to make sure my readers noticed there is now an Internet site that allows you to model circuits without the need to buy or download software.

The CircuitLab Website explains that: "We are happy to announce the launch of CircuitLab, the first Web-based circuit simulator with the power and accuracy needed for board-level design tasks. CircuitLab is now available free of charge to practicing electrical engineers, engineering students, and electronics hobbyists around the world."

CircuitLab works with Windows, Mac and Linux operating systems. Recommended browsers are Firefox or Google Chrome. Circuit designs can be shared simply by cutting and pasting a URL.

CircuitLab has posted on its Website some questions that its tool could answer. These include:

  • • If I use my microcontroller's digital PWM module for audio output, how will my low-pass filtering affect the signal before it goes into my speakers?
  • • Is my 1N4148 diode good enough to clamp the inductive voltage spike from my solenoid, and if not, how about the 1N5817?
  • • What's the bandwidth for this TL082 op-amp as a gain-of-100 inverting amplifier?
  • • Can I build a simple LED current regulator using a LM317 adjustable voltage regulator, and can I do it using just one transistor instead?


CircuitLab notes in its comments on uses for practicing engineers:

"Our user-friendly schematic capture tool lets you explore the design space in a fraction of the time of traditional tools. SPICE-like models with a mixed-mode simulation engine help you apply one tool to a wide range of design tasks, from digital to analog, DC to VHF and beyond."

You can take it for a spin at www.circuitlab.com.

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. As vice president of Broadcast Technology for NBCUniversal Local, H. Douglas Lung leads NBC and Telemundo-owned stations’ RF and transmission affairs, including microwave, radars, satellite uplinks, and FCC technical filings. Beginning his career in 1976 at KSCI in Los Angeles, Lung has nearly 50 years of experience in broadcast television engineering. Beginning in 1985, he led the engineering department for what was to become the Telemundo network and station group, assisting in the design, construction and installation of the company’s broadcast and cable facilities. Other projects include work on the launch of Hawaii’s first UHF TV station, the rollout and testing of the ATSC mobile-handheld standard, and software development related to the incentive auction TV spectrum repack.
A longtime columnist for TV Technology, Doug is also a regular contributor to IEEE Broadcast Technology. He is the recipient of the 2023 NAB Television Engineering Award. He also received a Tech Leadership Award from TV Tech publisher Future plc in 2021 and is a member of the IEEE Broadcast Technology Society and the Society of Broadcast Engineers.