A 400W (1kW Peak) 100A Electronic Load Using Linear MOSFETs

I bought a couple of IXYS linear MOSFETs (IXTK90N25L2) a while ago to test their capabilities when used as electronic load, and the result was quite impressive. So I decided to build another electronic load using both MOSFETs. As you can see in the video towards the end, this electronic load can sink more than 100 Amps of current while dissipating more than 400W continuously and can withstand more than 1kW ...

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HSN-1000 Nuclear Event Detector

DDC’s HSN-1000 radiation-hardened Hybrid Nuclear Event Detector (NED) senses ionizing radiation pulses generated by a nuclear event, such as the detonation of a nuclear weapon, and rapidly switches its output from the normal high state to a low state with a propagation delay time of less than 20ns. The active low Nuclear Event Detection signal (NED) is used to initiate a wide variety of circumvention functi ...

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From Trash to Treasure: How to Resurrect a Minitel Terminal

One of us (Mailland) grew up in Paris in the 1980s, surrounded by advertisements for racy “pink” chat rooms, accessible through terminals connected to France’s Minitel network. They were a lucrative part of the wider Minitel economy, which also let you send messages, check bank balances, and read news. By 2000, as the Internet displaced the Minitel network, the billboards started being replaced by piles of ...

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Nuclear physics applied in smoke detectors

Not many people know, but in some smoke detectors, radioactive materials play an essential role. Today I will present one of those devices, and my -successful- attempt to reverse engineer it and get the circuit diagram. Those smoke detectors use a small amount of Americium-241 (chemical symbol: Am) obtained in nuclear reactors as a decay product of Plutonium-241. Am241 emits mainly alpha particles, but also ...

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Semiconductor radioactivity detector

Currently I'm trying to make a working version of a radioactivity detector that uses semiconductor as a sensor. It's a different approach than Geiger-Muller detectors or ionization chambers, more complicated, but also much more interesting. While Geiger-Muller counters can only provide information about the amount of particles in a period of time, semiconductor detectors can also measure their energy, so it ...

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Scalar Network Analyser

DuWayne and I have been corresponding for a couple of years, sharing mutual interests. I was pleased to be able to give his work a shout in both the printed and  'spoken' version of my talk at this year's Four Days in May event in Dayton and - more importantly - to catch up with the man in person for a quick eyeball QSO. I also got a PCB for SNA Jr, which has been sitting on the bench for months - until las ...

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Load switch with self-resetting circuit breaker

The simple current-limiting load switch shown in Figure 1 will be familiar to most readers. In this circuit, a high level signal applied to the input switches on MOSFET Q2, which energizes the load. The load current is limited by negative feedback applied via Q1. In most applications, the current flowing via R2 into Q1's base will be very small compared to the load current IL, so the voltage VCS developed a ...

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12$ 30MHz signal generator using Arduino

A signal generator is an electronic device that generates electronic signals and waveforms. These electronic signals are either repeating or non-repeating as per the requirements and field of applications. It is generally used in designing, testing, troubleshooting and repairing electronic devices. A signal generator can generate various kinds of waveforms. Most common are the sine wave, square wave, sawtoo ...

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FFTs and oscilloscopes: A practical guide

The FFT (Fast Fourier Transform) first appeared when microprocessors entered commercial design in the 1970s. Today almost every oscilloscope from high-priced laboratory models to the lowest-priced hobby models offer FFT analysis. The FFT is a powerful tool, but using it effectively requires some study. I'll show you how to set up and use the FFT effectively. We’ll skip the technical description of the FFT, ...

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How to Build a Class-D Power Amp

The mighty Class-D amplifier—build one yourself and be amazed by its efficiency. The heat sink barely gets warm! Have you always wanted to build your own audio power amplifier? An electronic project where you not only see the results but also hear them? If your answer is yes, then you should continue reading this article on how to build your own Class D amplifier. I will explain to you how they work and the ...

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ICS501 simple frequency multiplier

Today I made a high frequency multiplier using a single component: the ICS501 PLL clock multiplier IC. This chip provides 2x, 5x, 8x (and more) clock multiplication using an internal phased-lock loop (PLL). At less than a dollar on eBay, $1.55 on mouser, and $0.67 on Digikey, they don’t break the bank and I’m glad I have a few in my junk box! I have a 10MHz frequency standard which I want to use to measure ...

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Cheap homemade 30 MHz – 6 GHz vector network analyzer

Introduction Vector network analyzer (VNA) are used to measure scattering parameters of high frequency circuits. When frequency is high enough the reflections of the waves start to matter and distributed effects need to be taken into account. VNA can be used to analyze reflection and transmission coefficients of circuits at high frequencies. For example ideally antenna would radiate all the energy it gets, ...

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