I got a link from Quantsuff, about making jewelry out of Nixie tubes. Bill ‘Botronics‘ Sherman replied that Nixie tubes need 140 to 170 volts at 2 milliamps. Meanwhile, I’ve got ten thousand or more of the Dionics DTN-205 transistors in my parts bins that were made for driving Nixies and VFDs. I liked Bill’s single Nixie clock, it reminds me of some old HP test equipment.
Quantsuff has been making schematics at Circuitlab.com, here is his latest. I think that six LEDs are going to be a very big burden for a 1N4148, which is going to have a very high forward voltage drop; the best analogy that I can think of is trying to fill the sink (LEDs) through a soda straw (diode). I have often noticed that when I put a second 1N4148 in parallel with the original one, it helps and the LED will get somewhat brighter. This indicates to me that the single one is being pushed past its limits, and a higher current diode is needed (see my note below). The 1 amp Schottky diode (1N5817) will give much better performance, especially if you use a 2SC2500. You will need to put 4 or 5 2N4401s in parallel to equal the 2SC2500. Get the highest gain 2SC2500D if you can – I’ve found they do a very good job of lighting multiple LEDs.
Speaking of parts, I ordered some IRFZ34 MOSFETs from Avnet, and they notified me this late afternoon that the parts had been shipped. Oddly, though, the parts were sitting on my doorstep when I got home, even before they notified me! Could this be an example of teleportation? 😉
Speaking of clocks and jewelry, one of the guys at work has a wristwatch that has a dark face, and when he taps the face, it lights up blue and white LEDs that indicate the time. Looks cool, but will the batteries last long? He says the LEDs of today use much less power than the LED watches of decades ago, so it shouldn’t be a problem. Decades ago, Hewlett Packard came out with the HP-01 watch, which used LEDs, but it was extremely expensive – in the late ’70s, $650 was a lot of money.
Speaking of clocks, I saw somewhere that a girl had invented a cool alarm clock that has wheels. When the alarm goes off, the clock jumps off the table and rolls across the floor, forcing you to get out of bed to shut it off. I think the name is Clocky. I saw another alarm clock with a similar idea. The clock has a propeller that’s inserted in the hole in the top, and when the alarm goes off, the propeller takes off and lands across the room, and the alarm won’t stop until you put the propeller back in the hole.
I got a copy of Cy Tymony’s book “Sneaky Uses For Everyday Things”, and I’ve been perusing the pages. In one section he shows how to build a crystal radio from a penny. The penny is heated to form a copper oxide layer, which acts as a rectifier. Someday I might try that, but I’d rather use a germanium diode for a detector. The book is for those of us who have to go to extreme lengths; for example it shows how to make wire from aluminum foil or from the spring in a ballpoint pen (that must be difficult, because the steel is so springy). I found the survival techniques section to be the most useful. The book is paperback and about a half inch thick. It’s full of black and white hand drawn illustrations, which, in my opinion, would have been better if they were real pictures. I have ordered but not received a few of his other books, which, I’m assuming, are probably similar.
Note: The note became so long that I gave it its own blog following this one.
