Background of the 2N709 used in the CDC6600 supercomputer in the 1960s: <a href="https://cpldcpu.wordpress.com/2020/02/14/what-made-the-cdc6600-fast/" rel="nofollow noreferrer">https://cpldcpu.wordpress.com/2020/02/14/what-made-the-cdc66...</a><p><a href="https://www.computerhistory.org/revolution/digital-logic/12/329/1426" rel="nofollow noreferrer">https://www.computerhistory.org/revolution/digital-logic/12/...</a><p>The functionally similar NPN switching transistor to the ancient 2N709 is still available. Search for PMBT2369.<p>Acronyms, BJT: Bipolar junction transistor