Category Archives: spice

Circuit VR: Simple Buck Converters

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The first thing I ever built without a kit was a 5 V regulated power supply using the old LM390K. That’s a classic linear regulator like a 7805. While they are simple, they waste a lot of energy as heat, especially if the input voltage goes higher. While there are still applications where linear regulators make sense, they are increasingly being replaced by switching power supplies that are much more efficient. How do switchers work? Well, you buy a switching power supply IC, add an inductor and you are done. Class dismissed. Oh wait… while that might be the best …read more

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Circuit VR: Sink or Swim with Current Sources

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If you got your start in electronics sometime after 1980 your first project might well have been to light up an LED. Microcontroller projects often light up an LED, too, and a blinking LED is something of the “hello world” program for embedded systems. If you tried lighting up your LED with a 9 V battery directly — not that you’d admit to it — you found it would light up. Once, anyway. The excess current blows up the LED which is why you need a current-limiting resistor. However, those current limiting resistors are really a poor excuse for a …read more

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Open-source Circuit Simulation

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For simple circuits, it’s easy enough to grab a breadboard and start putting it together. Breadboards make it easy to check your circuit for mistakes before soldering together a finished product. But if you have a more complicated circuit, or if you need to do response modeling or other math on your design before you start building, you’ll need circuit simulation software.

While it’s easy to get a trial version of something like OrCAD PSpice, this software doesn’t have all of the features available unless you’re willing to pony up some cash. Luckily, there’s a fully featured free and open …read more

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Circuit VR: Oscillating Bridges

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Circuit VR is where we talk about a circuit and examine how it works in simulation with LT Spice. This time we are looking at a common low-frequency oscillator known as the Wien bridge oscillator.

What makes an oscillator oscillate? A circuit with amplification that gets the same amount of the output signal fed back into its input, in phase, will oscillate. This is the Barkhausen criterion. Here, we’re going to look into what makes an oscillator work in simulation, and gain some insight into what happens when there’s too much feedback and too little.

In particular, we’ll look at …read more

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Circuit VR: The Dickson Charge Pump

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There was a time when taking a low DC voltage — say a single battery — and converting it to a higher voltage was painful. Now, however, cheap and easy-to-use DC to DC converters are readily available. For some small tasks, though, these can seem like overkill. For example, consider a case where you need to supply a higher voltage for a MOSFET gate that doesn’t draw much current. Perhaps you need that higher voltage to trigger a microcontroller’s programming mode and nothing else. The current draw is minimal, and a full-blown DC to DC converter is overkill. For cases …read more

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Friday Hack Chat: Simulating Analog

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Simulation is a valuable tool for any hardware developer. Instead of building hardware for a long debugging session, you can emulate a microcontroller and blink your lights with some Javascript. Instead of working on a Bluetooth protocol for your fitness wearable, you can just whip up some Javascript and get it working that way. Once all your Javascript is in order, then you can finally move over to hardware. It saves development time, and it saves money.

But this is all digital. What do you do if you’re working on an analog system? Lucky for you, there’s a system built …read more

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Minecraft and Forge: Try This Amazing Way to Visualize Logic

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I’ve got virtual circuits on the mind lately. There are a myriad of tools out there that I could pick up to satisfy this compulsion. But the one I’m reaching for is Minecraft. I know what you’re thinking… a lot of people think Minecraft is getting long in the tooth. But chances are you never tried some of the really incredible things Minecraft can do when it comes to understanding logic structures. This goes way beyond simple circuits and easily hops back and forth over the divide between hardware logic and software logic.

Traditional Circuit Simulation

Circuit simulation is a …read more

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LTSpice for Radio Amateurs (and Others)

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We don’t think [VK4FFAB] did himself a favor by calling his seven-part LTSpice tutorial LTSpice for Radio Amateurs. Sure, the posts do focus on radio frequency analysis, but these days lots of people are involved in radio work that aren’t necessarily hams.

Either way, if you are interested in simulating RF amplifiers and filters, you ought to check these posts out. Of course, the first few cover simple things like voltage dividers just to get your feet wet. The final part even covers a double-balanced mixer with some transformers, so there’s quite a range of material.

We like LTSpice. It …read more

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Make Mulled Wine With A Processor Heatsink!

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Now, over the holiday season there seems to be a predilection towards making merry and bright. As many an engineer and otherwise are sure to note, fine alcohols will facilitate this process. One such warm holiday beverage is mulled wine; there are many traditions on how to make it, but a singular approach to preparing the beverage would be to re-purpose an old PC and a CPU liquid cooling unit into a mulled wine heating station.

Four years ago, [Adam] found himself staring at a pile of mostly obsolete PCs in his IT office and pondering how they could be …read more

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Make Mulled Wine With A Processor Heatsink!

Posted on by

Now, over the holiday season there seems to be a predilection towards making merry and bright. As many an engineer and otherwise are sure to note, fine alcohols will facilitate this process. One such warm holiday beverage is mulled wine; there are many traditions on how to make it, but a singular approach to preparing the beverage would be to re-purpose an old PC and a CPU liquid cooling unit into a mulled wine heating station.

Four years ago, [Adam] found himself staring at a pile of mostly obsolete PCs in his IT office and pondering how they could be …read more

Continue reading Make Mulled Wine With A Processor Heatsink!→