Ok #vintageElectronics nerds! tell me about these things…

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

They’re in a PSU made for the British Post Office in 1972

The brown stripe seems to denote the + end, but what does the other stripe mean?

#Electronics #TelephoneExchange #Telephone #phone #phoneExchange #strowger #hamRadio #AmateurRadio