lpbkdotnet<p>Ok <a href="https://mstdn.social/tags/vintageElectronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>vintageElectronics</span></a> nerds! tell me about these things…</p><p>The “MR” designation denotes some kind of diode (it stands for Metal Rectifier, a notation hangover from before silicon/germanium diodes) and they’re obviously arranged as full bridge rectifiers</p><p>They’re in a PSU made for the British Post Office in 1972</p><p>The brown stripe seems to denote the + end, but what does the other stripe mean?</p><p><a href="https://mstdn.social/tags/Electronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>Electronics</span></a> <a href="https://mstdn.social/tags/TelephoneExchange" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>TelephoneExchange</span></a> <a href="https://mstdn.social/tags/Telephone" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>Telephone</span></a> <a href="https://mstdn.social/tags/phone" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>phone</span></a> <a href="https://mstdn.social/tags/phoneExchange" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>phoneExchange</span></a> <a href="https://mstdn.social/tags/strowger" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>strowger</span></a> <a href="https://mstdn.social/tags/hamRadio" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>hamRadio</span></a> <a href="https://mstdn.social/tags/AmateurRadio" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>AmateurRadio</span></a></p>