I live in a remote place where it's often impractical to try to get the exact part I want, either for replacement or for a new project, and that was even more so 15-20 years ago when I was still actively involved in repair work. The only practical option was to stock a popular device that can substitute for a wide range of types in its class - BU508A for TV HT output, BC547B and
2SC1815 for low-power low-frequency amp, and so on.I clearly recall keeping several BT135 SCRs (and BT136 triacs) - or so I thought. Something made me think about it today and I searched for a datasheet in an idle moment, but all of the half-dozen sites I regularly use turned up blanks. Even a Google search for BT135 didn't find anything. It's as if such a device never existed. Is my memory playing tricks on me?