> I need help with how much current a regular mains transformer would need for > the center tapped filament winding for six NIMOs. > > The filament for a NIMO is specified at 1.1V AC or DC +/-0.15V at some 0.2A. > The cold resistance of the filament is some 2.1 Ohm. > > Do I need to specify some overhead for the heater transformer to be able to > power six NIMOs or do I just need 1.2A current capability (6*0.2A)?
1.2A should be sufficient. The cold filaments will attempt to draw more, but the transformer will be unable to supply it, so the voltage will drop initially, which is what you want: this will give a gentler warmup than smacking them with full voltage would. It is, of course, possible to add more circuitry for an even softer start, but a transformer sized for the equilibrium load is pretty simple and works well. - John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/4F9CD132-40E5-470E-9065-E43B5BEAF3F8%40mac.com. For more options, visit https://groups.google.com/d/optout.
