Our beloved silicon-based transistors can “only” work at temperatures up to 550° F (around 290° C), which is much more than what’s needed for most general-purpose applications. But those don’t include a nuclear reactor, obviously! (Unless you have one at home. Do you?)
University of Utah engineers have developed tiny plasma-based transistors that can withstand temperatures up to 1,450° F (almost 800° C) and work with ionizing radiation. Since plasma itself is ionized gas, it can even be said that nuclear radiation contributes to proper functioning of these devices. Besides, current plasma-based transistors are about 500-µm long, while these newcomers measure 1–6 µm (!).
[via Elektor Electronics]
March 20, 2014 – University of Utah electrical engineers fabricated the smallest plasma transistors that can withstand high temperatures and ionizing radiation found in a nuclear reactor. Such transistors someday might enable smartphones that take and collect medical X-rays on a battlefield, and devices to measure air quality in real time.
“These plasma-based electronics can be used to control and guide robots to conduct tasks inside the nuclear reactor,” says Massood Tabib-Azar, a professor of electrical and computer engineering. “Microplasma transistors in a circuit can also control nuclear reactors if something goes wrong, and also could work in the event of nuclear attack.”
Tiny Transistors for Extreme Environs - [Link]
Kerry Wong writes:
Transistors operating in their avalanche regions are often used to generate fast rise pulses (see avalanche pulse generator using 2N3904). Many transistors can also avalanche when the connections to collector and emitter are reversed. When operating in reverse avalanche region, these transistors are sometimes referred to as negistors.
Because the asymmetry and doping differences between the base-emitter and base-collector junctions, the avalanche voltages for reversely connected BTJs are usually magnitudes lower than their normal avalanche voltages. Here, I decided to test a few different transistors and see at what voltages the reverse avalanche occur.
The circuit I used is a simple LED flasher, similar to what was described here. As with any circuit that exhibits negative differential resistance, the principle of operation is quite simple. The capacitor is charged via a current limiting resistor…
BJT transistor in reverse avalanche mode - [Link]
Bill uses a replica of the point contact transistor built by Walter Brattain and John Bardeen at Bell Labs. On December 23, 1947 they used this device to amplify the output of a microphone and thus started the microelectronics revolution that changed the world. He describes in detail why a transistor works by highlighting the uniqueness of semiconductors in being able to transfer charge by positive and negative carriers.
How the first transistor worked - [Link]
by Rick Robinson:
A research collaboration consisting of IHP-Innovations for High Performance Microelectronics in Germany and the Georgia Institute of Technology has demonstrated the world’s fastest silicon-based device to date. The investigators operated a silicon-germanium (SiGe) transistor at 798 gigahertz (GHz) fMAX, exceeding the previous speed record for silicon-germanium chips by about 200 GHz.
Although these operating speeds were achieved at extremely cold temperatures, the research suggests that record speeds at room temperature aren’t far off, said professor John D. Cressler, who led the research for Georgia Tech. Information about the research was published in February of 2014, by IEEE Electron Device Letters.
Silicon-Germanium Chip Sets New Speed Record - [Link]
A small, simple AM receiver project. This AM receiver can pick up medium wave stations in your area
This circuit can use general purpose transistors, and in this example there are 3 BC109C transistors. In this schematic and BOM there is a 200uH inductor and a trimmer 150-500pF capacitor, though these parts can be salvaged from an old AM radio, to preserve the directional nature of a tuning coil, and an adjustment knob (plate capacitor) that work well for radio reception.
The 120k resistor is for regenerative feedback between the Q2 NPN transistor and the input to the tank circuit. The value of this resistor is important to the performance of the entire circuit. In fact, it may be better to replace the fixed value with a variable resistor paired with a fixed resistor to adjust the oscillation and sensitivity of the circuit. All the connections in this circuit should be short to minimize interference.
Performance of the circuit will vary depending on stray capacitance in your layout, the inductor winding/core/length, etc. Changing values of some of the capacitors, or adding them, as well as a potentiometer in the feedback loop can help with the performance of the receiver. With such a small circuit that is affected so much by its construction and its environment, a lot of hand tuning and experimentation will be fun, instructive, and possibly necessary to make it work best.
Simple AM Receiver Project - [Link]
This is the first book of Giorgos Lazaridis covering the BJT Transistor Theory. The purpose of this book it to help the readers understand how transistors works and how to design a simple transistor circuit. It is addressed to amateur circuit designer with little or no previous knowledge on semiconductors. The book is written to be easy to follow, so it keeps mathematical formulas as simple as possible. Feel free to download and read it. More topics will be covered later.
The BJT Transistor Theory - [PDF]
Hemal Chevli blogged about his transistor tester project:
It has mega-8 as the brain, lcd to show specs of the transistor like which pin is which, what type of transistor it is eg NPN,PNP, N-MOSFET,P-MOSFET, etc., many components can be tested like different types of transistor, diodes, resistors etc, the good thing about this is that it also shows which leg is which, no need to open the data sheet
Transistor tester project - [Link]
TraId – is a Transistor type & pinout identifier:
TraId is a really low cost version of the Part Ninja. It’s made to only identify the pinout and type (NPN/PNP) of a transistor and display the results on eight LEDs. Currently the firmware only handles BJTs but I think FETs should be possible as well.
TraId – Transistor type & pinout identifier - [Link]
These recent breakthroughs in electrical component technology are likely to have a significant impact on the electronics industry – and on people’s everyday lives.
Your’e probably aware of the superstar conductor of the future, Graphene: “A wonder material that is the world’s thinnest, strongest and most conductive material with the potential to revolutionise diverse applications; from smartphones and ultrafast broadband to drug delivery and computer chips”.
New electronic components will change lives in 2014 - [Link]
Fully depleted silicon transistor are much promising for future developments. Xavier Cauchy writes:
To date, transistor scaling has continued in accordance with Moore’s Law down to 32 nm. Engineering challenges, however, are forcing chipmakers to compromise performance and power efficiency in order to reach smaller nodes – unless they switch to new technologies that help better solve these challenges. Today, the semiconductor industry is starting to deploy such new technologies, largely relying on “fully-depleted” transistors for continued scaling and performance gains.
Fully depleted silicon technology to underlie energy-efficient designs at 28 nm and beyond - [Link]