Hi John- I ended up grabbing one of these cheap fly swatters to test with. Any idea of the current these put out?
Thanks, Dylan On Aug 7, 2016 12:25 PM, "John Rehwinkel" <[email protected]> wrote: > > 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 [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/5C579590-1622-45C1-8A3C-61FFFD941113%40mac.com. > For more options, visit https://groups.google.com/d/optout. > -- 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/CAJrqPH_La3geAQjp84O3QbgQN72-SGbxokMMcbo5NyZczA8JMw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
