Replacing Selenium Rectifiers

Old radios often had selenium rectifiers to convert AC to DC. The problem is that the old units, dating back to 1933, are prone to failure and to release dangerous chemicals like hydrogen selenide.…

Comparing AliExpress Vs LCSC-Sourced MOSFETs

These days, it’s super-easy to jump onto the World Wide Web to find purported replacement parts using nothing but the part identifier, whether it’s from a reputable source like Digikey …

An Open Source 6kW GaN Motor Controller

We don’t know how you feel when designing hardware, but we get uncomfortable at the extremes. High voltage or current, low noise figures, or extreme frequencies make us nervous.  [Orion Serup…

The 555 As A MOSFET Driver

To drive a MOSFET requires more than merely a logic level output, there’s a requirement to charge the device’s gate which necessitates a suitable buffer amplifier. A variety of differen…

Making A Solid State 6AK8 Tube

[M Caldeira] had a project in mind: replacing a common vacuum tube with a solid-state equivalent. The tube in question was an EABC80 or 6AK8 triple diode triode. The key was identifying a high-volt…

Introduction To MOSFET Switching Losses

Metal-oxide semiconductor field-effect transistors (MOSFETs) see common use in applications ranging from the very small (like CPU transistors) to very large (power) switching applications. Although…

Sketchy Logg Dogg Logging Robot Remote Control Hacking

When we last left [Wes] amidst the torn-open guts of his Logg Dogg logging robot, he had managed to revitalize the engine and dug into the hydraulics, but one big obstacle remained: the lack of the…

Spy Radio Setup Gets A Tiny Power Supply For Field Operations

[Helge Fyske (LA6NCA)] may not be an actual spy — then again, he may be; if he’s good at it, we wouldn’t know — but he has built a couple of neat vacuum tube spy radios in t…

Linear Power Supply’s Current Limiter Is A Lesson In Simplicity

Here at Hackaday we really like to feature projects that push the limits of what’s possible, or ones that feature some new and exciting technology that nobody has ever seen before. So what&#8…

Op-Amp Challenge: MOSFETs Make This Discrete Op Amp Tick

When it comes to our analog designs, op-amps tend to be just another jellybean part. We tend to spec whatever does the job, and don’t give much of a thought as to the internals. And while it …

FET: The Friendly Efficient Transistor

If you ever work with a circuit that controls a decent amount of current, you will often encounter a FET – a Field-Effect Transistor. Whether you want to control a couple of powerful LEDs, sw…

MOSFET Heater Is Its Own Thermostat

While we might all be quick to grab a microcontroller and an appropriate sensor to solve some problem, gather data about a system, or control another piece of technology, there are some downsides w…

DIY Fume Extractor With ATtiny13 Speed Control

Let’s be honest, commercially-available soldering fume extractors are cheap enough that you probably don’t need to build one yourself. But it still makes for a good starter project, esp…

Induction Heater Uses New Coil

Induction cook tops are among the most efficient ways of cooking in the home that are commercially available to the average person. Since the cook surface uses magnetic fields to generate heat in t…

Practical Transistors: JFETs

Transistors come in different flavors. Tubes used an electric field to regulate current flow, and researchers wanted to find something that worked the same way without the drawbacks like vacuum and…

Motorcycle Regulator By Popular Demand

A few weeks ago we posted a build of an avid motorcycle enthusiast named [fvfilippetti] who created a voltage regulator essentially from the ground up. While this was a popular build, the regulator…

Motorcycle Voltage Regulator Uses MOSFETs

For how common motorcycles are, the designs and parts used in them tend to vary much more wildly than in cars and trucks. Sometimes this is to the rider’s advantage, like Honda experimenting …

The Q2, A PDP8-Like Discrete Transistor Computer

[Joe Wingbermuehle] has an interest in computers-of-old, and some past experience of building computers on perfboard from discrete transistors, so this next project, Q2, is a complete implementatio…

Hackaday Links: January 2, 2022

That sound you may have heard in the wee hours of Christmas morning had nothing to do with Santa; rather, it was the sound of a million astronomers collectively letting out their breath around the …

Laptop Gets Fixed By Simply Removing Problem Component

We wouldn’t go so far as to say “don’t try this at home”, but the way [Troy] brought an expensive (but out of warranty) laptop back to life is interesting, even if it should…