> uses a 555 timer ic as the controller... > My estimated total current at 170 volts DC would > be about 2.2 mA per tube. That would be about 13.2 mA > total. Is it worth experimenting with? > > ... seems quite tough to beat John Taylor's ... power supplies. > > Thanks. Chuck Richards
If your prime interest is to get your nixie clock up and running, then just buy one from Taylor. But then we have a diverse bunch here. A few might just be interested in building the supply, too. I've used just about anything that oscillates, to build a switching supply. The 555, MC34063, MAX1771, plus 4069 inverter, MC34072 dual op-amp, and LM393 dual comparator. I've also used extra IO pins off of uCs, and discrete transistors. The 555 is an old chip, dating back ~1969 (40yrs+), and still very popular in hobby circles. Efficiency isn't the best, but it can be regulated. I've found that I could get 12mA out of it without heatsinking the FET. Most of the online hobby sources carry it, as does your local Radio Shack. If your demands are not that great, it works just fine. I've been using the MC34063 lately. Initial experiments with this chip were quite disappointing. That's because I used the MK1 version, which as only a passive pull-down driving the FET. Adding an active pull- down (as in the MK1.5 version), or push-pull pair (as in the MKII version), greatly improved performance. About 4-years ago, I came across 500 MC34063 (in a DIP), and 100 TX137s (~IRF730) on eBay, for dirt (cheaper that cheap). I initially resold them in lots of 10, but sales were slow, and the return on investment was low. I layed out, and ordered 100 nixie supply PCBs. Built the supplies, and they sold quite quickly, plus I was pulling money out of Paypal account, instead of the other way around. I'm still selling supplies on eBay, but they have since gone surface mount, and they're not just for nixies, to avoid direct competition with Taylor. I still have over 200 of those MC34063 DIPs, which I use for all kinds of (one off) switchers, including +5V buck converters, which work better than your common 7805. The MC34063 is a very old chip, as switch-mode controllers go, and that's due to its versatility. -- 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.
