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 […]
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
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 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
Load switch with self-resetting circuit breaker Continue Reading
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
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
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
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
Cheap homemade 30 MHz – 6 GHz vector network analyzer Continue Reading
I’ve had a Siglent SDS1102CML two channel 100 MHz bench scope here for the last two years. I demand a lot from my test equipment so had low expectations when it arrived. After all, how good can a $359 unit be? Turns out, quite a good for the price. I reviewed it here. But the
The “I’m Fine” project is about monitoring the well being of especially lonely elderly people, who may not have daily contact to the family. Things used in this project Hardware components Arduino MKR1000 × 1 Arcade style button (60 mm diameter) with builtin LED light. I chose this type of button as I’d like it
