Fair enough, but for any of the sort of applications we're talking about you're never going to need a higher PIV than 400V. Even if the back EMF were very high, that's in the forward-conducting direction, so the PIV is irrelevant and, when used for this sort of purpose, the highest 'reverse voltage' it would encounter would be that of the supply - 12V/24V/whatever.Ok thanks @JohnW2 to be fair I have enough 4004 for my needs so im gonna get a few 4007 as there less than a couple a quid, scanning the net 4007 appears to be quite commonly mentioned for maglocks ( though I respect what you say about unnecessary in most cases) ... I can at least add them to increase my range of Electronic bits I have for Fire alarm repairs and the like.
He must be having a very atypical day, since winston is correct again As BS3036 says, the first character of that ("JEDEC") semiconductor naming system is a number, one less than the number of wires/connections - hence 1 for a diode, 2 for a bipolar transistor/FET and 3 for a dual-gate FET. The second character is always an "N". You must have come across transistors with 2Nxxx or 2Nxxxx numbers, haven't you?Out of interest I called them "IN4xxx" ( as it was hard to read off the diode) as did you, or was you patronising me but Winston called them "1N4xxx" as do the Ebay listings, so what are they
Kind Regards, John