> I took the bait and picked up 4 of these to add to my future projects pile. > That said, I've never experimented with voltages beyond the dekatron range. > I don't know that I'm interested at this point in building my own kV PSU > (although I would be eventually). Can anyone recommend a relatively > inexpensive off the shelf PSU to drive these with?
I like using a CCFL supply with a voltage doubler. Since only a tiny amount of current is required, you can also get away with a lower voltage supply (like a Tayloredge) and quite a few stages of multiplication. Another cheap and common source is those handheld electric flyswatters (which will give around 2kV from a pair of AA cells). Negative ion generators are cheaply available as surplus, and can also furnish several kilovolts easily. Copiers and laser printers can be a source (their corona wires use high voltage), or ozone generators, CRT and plasma TVs, and electrostatic dust precipitators. > According to the datasheet, I should be looking for 2.5kV on the anode, > with 1.1V on the filament. I'm not sure exactly how to drive the grid. There are ten grids, one for each digit. You can actually drive them directly with CMOS logic, if the filament voltage is appropriate, they only take a few volts. You drive one a few volts positive (relative to the cathode) to light that digit, and drive the rest of them a few volts negative (also relative to the cathode: in CRTs, all voltages are measured relative to the cathode). A common lashup is like in the data sheet, where pulldown resistors keep the grids held low, and transistors are used to pull one positive at a time to light the digit wanted. > Does the grid consist of the cathodes? The filament is actually the cathode. The grids are the apertures for each digit. You can drive the filament using an ordinary transformer, with dropping resistors or capacitors calculated to deliver the rated amount of power. You can even drive it directly from a pair of 5V inverters operated out of phase, along with appropriate dropping resistors or capacitors. In this instance, capacitors are preferred, so you can bias the filament to the DC voltage you want to make the grids voltages easy to work with. If you're working with 10V CMOS, and bias the filament to +6V, you can simply ground the grids that are off, and connect the one you want to turn on to +10V. This will give the grids the -6V/+4V swing (relative to the cathode) that they're supposed to see. > Apologies, but I have zero CRT experience at this point, and any pointers > would be appreciated. I'd like to at least be able to test these when they > come in. The easiest test is a continuity test to make sure the filament isn't broken. However, I'm guessing you want to see one lit. Go find one of those electric flyswatters for the anode voltage (they're a few dollars), and be careful, you don't want to touch high voltage, and have your reflex throw your tube across the room! - 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 neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/5C579590-1622-45C1-8A3C-61FFFD941113%40mac.com. For more options, visit https://groups.google.com/d/optout.
