Bipolar junction transistors (BJT)
I found an information technology department in an old abandoned building. The warehouse was full of all kinds of obsolete electronic devices. Including radio: transistors, field-effect transistors and bipolar, thyristors, resistors, capacitors, microcircuits and so on.
It is clear that the valuable has already been disposed of, but nevertheless, I collected everything and took it home.
And at home I organized a photo session ...