Matthew Twyman GW6KOA delivered an interesting talk on the humble FET last night, he explained how they were made and the consequences of the production processes… he explained how FETs are often made up of several transistors in one package to give more gain, and how devices with flaws in are sold as lower power devices… if you look at the photos you will see on device has a red dot and a blue dot. These dots indicate the half of the package that is faulty, this device photographed is a 3W device instead of the normal 6W. Anything to reduce wastage in production!
One of the devices Matthew showed us was a device he had been a part of the team who designed it, a fibre optic receiver for use in the bradband networks. He was also brave and showed us a preamp he was prototyping for 2m using a readily available device suitable for microwave, he is still experiencing unexpected results at the lower frequency but is certain that he will be able to crack the design!
He stressed the importance of not opening FET devices as they are often made using Beryllium Oxide which is safe while it is a ceramic, but can be lethal if it becomes a powder again.
He did show us a device under a microscope that had been opened (which did not contain Beryllium Oxide). It was amazing!
It was a very interesting talk. Thank you Matthew.
73 de Emyr 2W0MWM