When you say next to and IC, do you mean from the
+5V, to ground?
Hi Shane!
In this case next means with the shortest possible path between the
power supply terminals to be decoupled.
When one uses bussbars under logic circuits it means one on the head
of each IC. For really sensitive and / or
On Jul 20, 10:36 am, neutron spin mrstan...@charter.net wrote:
I have a minor comment on the circuit designIf you are going to
use a battery the 7805 will waste power. How can this be avoided? One
fix would be to use a Low-dropout regulator...using the walwart of
course you are not
Decoupling should be done EVERY time on EVERY chip - analogue or
digital - right adjacent to the supply pins.
It costs pretty much nothing, and saves a whole bunch of trouble. Just
do it.
Part of the need to do this is that chips today are much much faster
than they used to be, so where
Capacitors still kind of confuse me, and the terminology has me scratching
my head. I understand what they do, but calculating them is still something
I don't understand. When you say next to and IC, do you mean from the
+5V, to ground?
Resistors I got, Capacitors frustrate me...
Shane
On
Hi Shane,
When you say next to and IC, do you mean from the +5V, to ground?
Yep. There are some IC sockets who have a 100nF capacitor connected from
the pin on the bottom left to the pin on the top right, i.e. the most
common IC power pins.
Resistors I got, Capacitors frustrate me...
Wow, thank you for the headache so early in the morning! I got my one tube
circuit working, but going to a much larger uC, and more tubes, more noise
is bound to come up, so now that I know how to decouple with caps, I'll be
sure to add them. Thank you all.
Such a great group. I hope you all
Shorter answer:
The higher the frequency, the more a capacitor looks like a short.
The lower the frequency, the more a capacitor looks like an open.
We use those little 0.1uf ceramic caps next to fast switching IC's
because those IC's insert fast transients onto the power rail.
Capacitors
The higher the frequency, the more a capacitor looks like a short.
The lower the frequency, the more a capacitor looks like an open.
We use those little 0.1uf ceramic caps next to fast switching IC's
because those IC's insert fast transients onto the power rail.
Capacitors that are placed
| | Resistors I got, Capacitors frustrate me...
|
| It is not that hard to understand: Capacitor act just like resistors
for
| AC. The higher the frequency, the more current can flow ...
| The complex impedance is Z := 2*Pi*(-i)/f*C, where f is
| frequency in Hertz, C is the capacity in Farad and
I have a 330 ohm on the +5v of the 74141, and the tube itself, has
a 10K on the anode. No other resistors or caps are in this circuit. Maybe
I got lucky last time when this worked, but this time, it's not happening.
Shane
Hi Shane!
TTLs don't need current limiting of any kind in their
Hi,
I think the problem can be circled fairly easy:
Create some sample code that is supposed to have the Nixie tubes read
out a static 12:48 for example. Then check the corresponding BCD
inputs on each chip. If the right number appears there (in BCD format,
that is) and the chip displays a
Thank you everyone for the suggestions. I'll remove the current limiting
resistor to the 74141, I'll check the Picaxe, and 74141, and I'll simulate
my code to make sure pins are going high low at the same time.
I'll check in later
Shane
On Wed, Jul 20, 2011 at 4:48 AM, jb-electronics
Unbelievable. I yanked out the four data wires, (picaxe to 74141), double
checked them, and NOW, I get 4,5,6,7 What is going on!?
Shane
On Wed, Jul 20, 2011 at 4:48 AM, jb-electronics webmas...@jb-electronics.de
wrote:
Hi,
I think the problem can be circled fairly easy:
Create some
Unfortunately, i'm still at the breadboard stage, so no soldering yet. I
forgot a lot about nixies, and programming, so I'm taking baby steps.
Keep these suggestions coming, eventually we'll figure it out.
Shane
On Wed, Jul 20, 2011 at 8:40 AM, jb-electronics webmas...@jb-electronics.de
Well, not knowing the schematic...
If you were binary at some point and had the 4bit high, that would give you
the 4,5,6,7 instead of 0,1,2,3
Michail
In a message dated 7/20/2011 6:42:55 A.M. Pacific Daylight Time,
mime...@gmail.com writes:
Unfortunately, i'm still at the breadboard
I was wondering about eddie currents, and crosstalk, but I have everything
as isolated as I can on the breadboard.
hmmm
On Wed, Jul 20, 2011 at 8:46 AM, jb-electronics webmas...@jb-electronics.de
wrote:
**
What do you use for connective wires? When they are poorly insulated
against each
This is in fact binary, I'm using the four outputs on my micro as the 4
high/low signals on the 74141.
Something unusual though. I unplugged the ground to the 74141, and it still
displayed the 4,5,6,7...
For some reason, I'm not getting a proper ground at the 7805 volt regulator.
I'll rewire the
On 7/20/2011 9:07 AM, Shane Ellis wrote:
Unbelievable. I yanked out the four data wires, (picaxe to 74141),
double checked them, and NOW, I get 4,5,6,7 What is going on!?
Sounds like the low 3 bits are connected correctly, and the high bit is
not connected. TTL chips like the 74141 will
I have a minor comment on the circuit designIf you are going to
use a battery the 7805 will waste power. How can this be avoided? One
fix would be to use a Low-dropout regulator...using the walwart of
course you are not concerned with battery life.
Rergards
Robert
On 20 July, 11:47, Shane
the battery was for the schematic, and initial breadboard testing. Thank
you for the input though! Wall wart power the tube nicely. Now, to move to
a bigger uC, and get four tubes running ( and singing)
Shane
On Wed, Jul 20, 2011 at 12:36 PM, neutron spin mrstan...@charter.netwrote:
I have
A suitable device could be the L4940V5 from ST .if you need less
current there are many others
Regards
Robert
On 20 July, 13:36, neutron spin mrstan...@charter.net wrote:
I have a minor comment on the circuit designIf you are going to
use a battery the 7805 will waste power. How
Could be bad breadboard...
-Adam
On 7/20/2011 6:46 AM, jb-electronics wrote:
What do you use for connective wires? When they are poorly insulated
against each other and they touch at some point, you might get some
crosstalk that disturbs your BCD signal.
Jens
Am 20.07.2011 15:42, schrieb
| Could be bad breadboard...
|
| -Adam
Good point ! The quality of modern 'solderless breadboards' (called
protoboards when I was a young whipper snapper) could be suspect.
I first used these back in the late 70's, and still have those, and
they still make great connections. But I bought some
Using a Picaxe( takes program fine, so thats working) the HVPS is
working, since the numbers still light up, the 74141 seems to be
working, it changes numbers at the right time, it just displays the
wrong numbers.
On Jul 19, 8:46 pm, Mimewar mime...@gmail.com wrote:
OK, so I have a tube
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