#Germanium transistor series#

In the next two years, the GT and UT researchers will develop actual circuits from SiGe that could be used on Europa, such as radios and microcontrollers. 'So, we worked literally for the first year to get the results that are in that paper, which is in essence definitive proof that what we claimed is, in fact, true-that SiGe does survive Europa surface conditions.'

'What had never been done was to use electronics like we did in that experiment,' Cressler said. They exposed SiGe HBTs to one million Volt electrons to a radiation dose of five million rads of radiation (200-400 rads is lethal to humans), at 300, 200, and 115 Kelvins (-160 Celsius). To answer this question, the GT researchers used JPL's Dynamitron, a machine that shoots high-flux electrons at very low temperatures to test SiGe in Europa-type environments. In effect, any technology designed for Europa's surface would not only need to be able to survive the cold temperatures but also the worst radiation encountered in the solar system. Unfortunately, as a moon of Jupiter, Europa sits squarely in those radiation belts. Like Earth, Jupiter also has a liquid metal core that generates a magnetic field, producing radiation belts of high-energy protons and electrons from the impinging solar wind. But it all starts with electronics that can function in Europa's extreme environment.Ĭressler and his students, together with researchers from NASA Jet Propulsion Lab (JPL) and the University of Tennessee (UT), demonstrated the capabilities of SiGe HBTs for this hostile environment in a paper presented at the IEEE Nuclear and Space Radiation Effects Conference in July. NASA plans to launch the Europa Clipper in 2024, an orbiting spacecraft that will map the oceans of Europa, and then eventually send a landing vehicle, Europa Lander, to drill through the ice and explore its ocean. The researchers are in year one of a three-year grant in the NASA Concepts for Ocean Worlds Life Detection Technology (COLDTech) program to design the electronics infrastructure for upcoming Europa surface missions. 'You can build it for what you want it to do on Earth, and you then can use it in space.' 'Due to the way that they're made, these devices actually survive those extreme conditions without any changes made to the underlying technology itself,' said Cressler, who is the project investigator. Cressler in the School of Electrical and Computer Engineering (ECE) and his students have been working with silicon-germanium heterojunction bipolar transistors (SiGe HBTs) for decades and have found them to have unique advantages in extreme environments like Europa. This will show up as a couple of millivolts difference on a digital multimeter's diode test scale or a slightly higher resistance on an analog VoltOhmMeter.Regents' Professor John D. The collector and emitter can be identified knowing the fact that the doping for the B-E junction is always much higher than for the B-C junction, therefore, the forward voltage drop will be slightly higher. The collector junction is almost always not a zenerific one and will instead avalanche at 40 or more volts.

#Germanium transistor series#

You can do it with two 9-volt batteries and a 3.3K resistor if you hook them all in series with a transistor, in one of the configurations the transistor's EB junction will zener at around 6 to 15 volts. The one with the higher voltage drop will correspond with the emitter of the transistor.įiguring out collector from emitter is a bit harder. I quote: If your multimeter does have a 'diode test' function that gives you the voltage drop across the forward-biased diode being tested, you can compare the voltage drop across the two diode candidates.