The Signal

  • After some Facebook chatter on last week’s blog , I think it deserves some follow-up. Here is the interview question that has bugged me for 41+ years: A 1V AC source is connected to a 1Ω resistor in series with a 1Ω reactance capacitor...
  • It’s time for some fun! I’ve known a few folks who have tormented colleagues with a resistor cube—equal resistors on all sides. So in case you’ve solved that one, let’s add a twist. In this cube, not all the resistors are...
  • SPICE is a useful tool to help check for potential circuit stability problems. Here is one simple way to do it: Figure 1 shows a non-inverting amplifier using the OPA211 with a couple of minor variations that are common in many applications. R3-C1...
  • Did you see last week’s resistor puzzle? Check it out if you missed it . Here’s the solution: We’re not accustomed to reading three-dimensional schematics so the first step is to redraw it clearly. There are three distinct paths from...
  • Is it possible to parallel two op amps to get twice the output current? We get this question periodically on our E2E forums. Though we may answer with a qualified “yes,” it tends to make us shudder just a bit. It can be done… but...
  • August 22, 2012 Anyone who has read a few of my blogs has seen that I simulate circuits in SPICE. You may know that Bob Pease was pretty opinionated about SPICE and once wrote, “SPICE takes away your ability to get good insights on what is happening...
  • Have you noticed?...it’s rare to find new generation op amps and other ICs in DIPs (dual-inline packages). Without volume demand, it’s not economically viable to offer new ICs in DIPs. Breadboarding with these newer fine-pitch micro-packages...
  • Jake, a respected veteran engineer in a power generation plant, retired with great congratulations and accolades. A few months later the plant suffered a major malfunction—a real meltdown with all systems involved. The engineering staff could not...
  • Bob Pease died a year ago yesterday. What a loss for us analog heads who struggle to make our circuits work. His wealth of knowledge and experience seemed limitless. His insight and intuitive explanations helped so many engineers understand their circuits...
  • A holiday week is a good excuse to stray a bit off topic so this is my chance to tell you about Goop. It is by far the most versatile glue I’ve found. Okay, I promise to tie this in (though weakly) to electronics. Goop comes in a fat toothpaste...