On Tuesday, February 24, 2015 at 5:40:53 AM UTC-5, Alex wrote:
>
> Those have been on ebay for a good while from the same seller, I was
> tempted a while ago but they are just too high a $ for my taste. The
> displays panels themselves are, if i recall from reading somewhere, a
> nightmare to dr
Greg -- regarding the resistor size and power dissipation, if there are 6
digits (7 in this case with the neons), can't you figure the resistor duty
cycle is 1/6th, and therefore smaller wattage resistors can be used? The
average dissipation is more like .043 watts, by my back-of-the-napkin math
On 2/24/15 6:38 PM, Joe Croft wrote:
Hi Yall,
Okay, I scoped the board and I have almost 500us of total dead time
between digits. This was measured on the digital outputs from the CPU.
My code is written in a way that I turn off all of the segment and digit
signals one at a time in a for loop so
Hi Yall,
Okay, I scoped the board and I have almost 500us of total dead time between
digits. This was measured on the digital outputs from the CPU. My code is
written in a way that I turn off all of the segment and digit signals one
at a time in a for loop so they are not all triggering at once. T
I used direct-drive on my first nixie project only because my gut-instinct
was to keep it as simple as possible; I've stuck with that ever since.
Too many postings about 'noisy nixies', choosing the correct
cathode-current, bleeding, flickering, RFI, etc. I've even seen
scary-looking blue arcs b
Greg,
I concur that these are fine things to do. I adjsuted my base-emitter resistor
so that it would have about 0.3V across it if the base were disconencted form
the circuit and the driving signal was on.
Also, short wires from the driver to the tubes are helpful to reducing
crosstalk. I ma
I think this is the problem: The base-emitter of the PNP is not shunted
with a resistor (see note from Terry). The purpose of the base-emitter
resistor is to provide a path for the leakage-current of the NPN predriver.
With the schematic as shown, roughly half of the NPN's leakage current goes
Joe -- the anode driver I "borrowed" from the open-source clock looks
slightly different than yours.
It uses the same transistors, but the MPSA92 has 100K directly across the
BE junction, and a 470K between the MPSA42 collector and the MPSA92 base.
In other words, imagine moving your R22 to
Does the issue happen more to certain tubes/digits than to others? If so,
it could have something to do with the layout of the traces: i'd be
especially worried about long runs of high voltage lines parallel to the
lines switching the transistors. E.g., in your PCB, the trace at the very
bottom
We need a class like this in Chicago!! I would be there in a flash!! :)
-joe
On Mon, Feb 23, 2015 at 11:14 AM, John Rehwinkel wrote:
> I'd been looking for a top one-to-one cold-cathode display making course
>
> So, last week I went up t'north and learnt more in the hours I was there
> that I h
Hi Yall,
I've attached a picture of the display pcb layout and a pdf of the
schematic for it. The cathode drivers are just the MPSA42 with a 100K ohm
base transistor and the collector is tied directly to the cathode and the
emitter is tied to ground.
-joe
On Mon, Feb 23, 2015 at 10:58 AM, gregeb
Those have been on ebay for a good while from the same seller, I was
tempted a while ago but they are just too high a $ for my taste. The
displays panels themselves are, if i recall from reading somewhere, a
nightmare to drive as they use glow transfer to scan in data, so
essentially gas based
On Tuesday, 24 February 2015 08:18:16 UTC, Paul Parry wrote:
>
> I can feel this wandering off Topic slight.. Again.. LOL
>
It doesn't matter in this case. Believe me :)
> What a wonderful use for a 5C/3023. I did mention earlier that I had a bit
> of a fondness for Vintage aircraft, I had a c
Hello Nick,
I can feel this wandering off Topic slight.. Again.. LOL
What a wonderful use for a 5C/3023. I did mention earlier that I had a bit
of a fondness for Vintage aircraft, I had a complete Vampire T11 in my
possession a few years ago XD515 (long story) not the smallest things to
house
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