CircuitLab Pivots from Circuit Simulation to Online Games

Apr 01 2012, 1:00 AM PDT · 2 comments »

(SAN DIEGO) -- CircuitLab today announced a transition from the field of online circuit simulation to online browser-based games with the launch of “Circuit-oids”, now available at

“Non-linear circuit modeling in the browser was a field we were happy to introduce to the world, but let’s be honest -- it was really hard. When our users started requesting custom behavioral sources and vacuum tube models, we started to realize that building software for the online entertainment market was a much easier technical task,” said Mike Robbins, CircuitLab’s developer of simulation components.

“We were in the middle of writing a new plotting library to give more powerful graphing tools to our users, but at some point we realized that we’d basically written most of a browser-based vector game engine. At that point, pivoting to the Circuit-oids model was a no-brainer,” said Humberto Evans, CircuitLab’s user interface developer. “Our online schematic editor made a lot of users happy, but the gaming angle lets us do that much more directly.”

Circuit-oids can be found at until further notice. If it happens to disappear in the near future, like Monday Morning, the developers suggest that there might be special ways to activate it within the CircuitLab editor.

International (IEC/European) Resistor Symbols

Mar 17 2012, 11:30 PM PDT · 7 comments »

While CircuitLab has a US-based team of developers, we've been pleasantly surprised by how much international attention our tool has received over the past few weeks. We've seen articles and posts about CircuitLab in Chinese, Czech, French, German, Greek, Italian, Japanese, Polish, Portugese, Russian, Swedish, and Spanish. In fact, we've got just about as many website visitors from Europe as we do from North America!

The resistor is the most basic of circuit elements, and it's often the most common discrete component in many analog circuits. Many Americans are used to seeing a "squiggle"-styled line segments like we've included in CircuitLab. However, in the rest of the world, the normal resistor symbol is just a simple outlined rectangle (the IEC-standard symbol choice).

Today we've added support for the IEC / European style resistor symbol. Simply double-click the resistor and change its display type "DISP" parameter from US to IEC. Everyone deserves to have a pleasant circuit-drawing experience, and CircuitLab is here to help!

In-browser Graphing Calculator (Happy Pi Day!)

Mar 14 2012, 4:25 PM PDT · 0 comments »

CircuitLab's simulation and plotting engine has the ability to evaluate arbitrary mathematical expressions. That makes it easy, for example, to plot the voltage across an element, such as "V(A)-V(B)" to plot the voltage difference between those nodes.

You can also try other powerful expressions, such as "P(R1)" to plot the power dissipation in element R1. This is especially useful for multi-terminal devices like transistors when you want to make sure that the power dissipation won't cause thermal problems or even device failure. Power users can also use these expressions in frequency-domain analysis, for example when evaluating the performance of differential amplifiers. Check out the documentation for more about plotting expressions in CircuitLab.

Many basic mathematical expressions can also be used when setting parameter values. For example, if we want to create an RC low-pass filter with a corner frequency of 60 Hz, and we have a resistance of 100 kOhms, we can double-click on the capacitor and enter a capacitance of "1/(2*PI*100k*60)" -- CircuitLab will compute the value automatically.

Since today is Pi Day, we thought we'd show off the fact that you can actually use a tiny subset of CircuitLab to act as an in-browser graphing calculator! In time-domain simulation mode, you can use expressions with "T" to plot functions of time, so for example "T^2" to plot a simple parabola.

You can get even fancier: "-0.5*9.81*T^2 + 20*T" would show the parabolic vertical trajectory of an object launched upwards at an initial vertical velocity of 20m/s. And "2.5*COS(2*PI*T)" would make the appropriate cosine signal. DC Sweep mode can also be used to create parameters that you can adjust on both sides of zero, or even plot against a logarithmic scale.

Check out this demo circuit for a few examples: