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Herald1360 · 24th Jan 2019, 7:12 pm

I think it's more likely because the 1N4007 will have the highest Vf of the group. You don't want the clamp turning on too soon. If HT+ shorts to LT+ it will be clamped at around 1.5V, low enough to be safe for the filaments but of course the diode is forward biassed. If HT+ shorts to HT- it'll be clamped more firmly by a short circuit!

24th Jan 2019, 7:12 pm	#15
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Roberts R66 diode MR2 I think it's more likely because the 1N4007 will have the highest Vf of the group. You don't want the clamp turning on too soon. If HT+ shorts to LT+ it will be clamped at around 1.5V, low enough to be safe for the filaments but of course the diode is forward biassed. If HT+ shorts to HT- it'll be clamped more firmly by a short circuit! __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O