Hi all- Just wanted to revisit this thread to provide an update on my learning process and ask for some additional advice... I was in Radioshack to grab a one off part I needed for something else, and on a whim decided to look at their transformers. I noticed they had one that does 25.2VAC out at 450mA. I ended up grabbing it and have finally gotten around to trying it out. I have not done any experimentation with transfomers at all yet, so I thought this would be a good opportunity.
Although I will probably not go with this approach as I start to design and build my own clocks due to the bulk and impracticality of using it in a small space, I figured this might work for my first VFD clock built on perfboard. I have successfully hooked light up one IV-11 with it, combined with a 1.5v DC battery on the filaments. I have a few questions...First, is there anything I should be worried about or need to think about when going the transformer route (other than doing something stupid and touching the mains side)? Second, does anyone have any recommendations on stepping down the voltage for the filaments without another transformer? I know another poster suggested not using the same power line for everything, but if I can figure out a compromise that I can live with for this particular experiment, I am open to it. I would like to keep AC power going to the filaments; that's the reason I don't want to use a separate filament supply in this case. As always, thanks to all for your help. I'm learning a great deal from this crowd, and am excited to put a prototype VFD clock together even if it is going to be ugly! As an aside, I'm very excited to build my dekatron spinner kit! I'm anxiously awaiting my OG-4s I have on order so I can put this baby together. It will be my first dekatron project. On Sat, Dec 31, 2011 at 8:02 AM, John Rehwinkel <[email protected]> wrote: > > I built a simple voltage multiplier as suggested out of two diodes and > two capacitors and plugged in a 12VAC as input. I got out around 36 volts > DC based on the caps I used (I am assuming that is the reason it was not > closer to 24volts. > > It's not your cap choice, it's how these doublers and multipliers work. > With little or no load, they charge to the peak > input voltage. Since AC varies, spending part of its time at low > voltages, to deliver the same power* as a DC voltage, > it also has to spend part of its time at higher than the equivalent DC > voltage. So 12VAC is generally really 12VAC RMS, delivered as a sine wave. > The peak voltage of a sine wave is 1.41 (the square root of 2) times the > RMS voltage, or > about 17 volts. The peak to peak (negative peak to positive peak) is > twice this, or about 34 volts - which is what you'd > expect from a doubler supply like yours. > > I hope I've shed more light than confusion on the issue! > > - John > > * into a resistive load - it gets more fun when reactance comes into play > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/neonixie-l?hl=en-GB. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
