Come on, folks. never hook anything directly to the power line. The
source is just too stiff. Use an opto. I used fiber optic isolation with
my big DC power supply.
Don
I used to agree, until actually tried it myself. Now this is how
I do my picPET 60 Hz data logging:
Dangerous.. A
David VanHorn wrote:
Come on, folks. never hook anything directly to the power line. The
source is just too stiff. Use an opto. I used fiber optic isolation with
my big DC power supply.
Don
I used to agree, until actually tried it myself. Now this is how
I do my picPET 60 Hz data logging:
Somewhere or another there should be a compromise that makes you happy...
you will, however, never achieve true safety as long as you are alive.
I am far more aware of this than you might suspect, but I do think that it is a
very good idea to know the risks involved.
An optoisolator is
David VanHorn wrote:
Somewhere or another there should be a compromise that makes you happy... you
will, however, never achieve true safety as long as you are alive.
I am far more aware of this than you might suspect, but I do think that it is a
very good idea to know the risks involved. An
Trust me, if you use any plug in consumer grade electronics, you already are.
Actually, we design plug-in consumer grade electronics here. No single point
of failure is allowed to present line current to the user.
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Let's not be obtuse on purpose, David.
David VanHorn wrote:
Trust me, if you use any plug in consumer grade electronics, you already are.
Actually, we design plug-in consumer grade electronics here. No single point of
failure is allowed to present line current to the user.
Let's not be obtuse on purpose, David.
No amount of dancing is going to turn this into a design that is safe by any
reasonable definition of the word.
Safe in terms of it hasn't killed anyone yet is probably true.
Safe in terms of you can trust this device not to cause a fire, no.
To quote
Do we think that failed shorted is rare?
http://www.navsea.navy.mil/nswc/crane/sd18/Public%20Documents/Resistors/ResistorsFailure.pdf
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Yes, the paper even says so.
The graph of failure rate is interesting. How useful is a graph
that shows the failure rate of a general purpose film resistor as
being from about 5E-10 to 8E-8 ?
In any case, they are saying that 5% of a (to be pessimistic) 8E-8
phenomenon results in a short
...@elec-solutions.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Monday, 28 November 2011, 18:56
Subject: Re: [time-nuts] Clocking a PIC16F628A from a Rubidium Standard
Let's not be obtuse on purpose, David.
No amount of dancing is going to turn
N.B. /tvb's adapter is NON-polarized.
Jerry
Don Latham wrote:Sorry, Brooke-I was not clear. I meant to not connect anything
toneutral at all, but rather to depend on the ground connection alreadymade in
the equipment for the low side of the signal, rather than a 1meg to neutral at
the plug.
On Sat, 26 Nov 2011 12:08:41 -0800
Tom Van Baak t...@leapsecond.com wrote:
Come on, folks. never hook anything directly to the power line. The
source is just too stiff. Use an opto. I used fiber optic isolation with
my big DC power supply.
Don
I used to agree, until actually tried it
On Fri, Nov 25, 2011 at 1:21 PM, Robert Atkinson robert8...@yahoo.co.ukwrote:
Hi,
Microchip cerainly condone using input protection diodes of PIC devices as
clamps. There are application notes for zero-crossing detection which
connect the input to the 115V AC line via a resistor. Note that
Come on, folks. never hook anything directly to the power line. The
source is just too stiff. Use an opto. I used fiber optic isolation with
my big DC power supply.
Don
Orin Eman
On Fri, Nov 25, 2011 at 1:21 PM, Robert Atkinson
robert8...@yahoo.co.ukwrote:
Hi,
Microchip cerainly condone
On Nov 26, 2011, at 10:36 AM, Don Latham wrote:
Come on, folks. never hook anything directly to the power line. The
source is just too stiff. Use an opto. I used fiber optic isolation with
my big DC power supply.
I don't disagree on isolation. I will say that Atmel's (and presumably
How did such a trivial circuit function for a one-unit application
trigger such a large philosophical discourse? I guess I'll put my
one-cent's worth in too. If you were designing to make a
mission-critical item, or millions of units, then every part and
every penny would count, so the finesse
Come on, folks. never hook anything directly to the power line. The
source is just too stiff. Use an opto. I used fiber optic isolation with
my big DC power supply.
Don
I used to agree, until actually tried it myself. Now this is how
I do my picPET 60 Hz data logging:
Simple 60 Hz AC Mains
well, grudgingly. only need the 1 meg to the hot side of the line, no
connection to the neutral needed, with 1 meg in there, normal ground
connections are going to supply the low side...It still lurks...
Don
Tom Van Baak
Come on, folks. never hook anything directly to the power line. The
source
Hi Don:
Not a good idea. There are a number of fault conditions that can cause Neutral to be tens of volts above ground. Tom's
circuit with a Meg in both the Hot and Neutral lines is much safer for you equipment.
Have Fun,
Brooke Clarke
http://www.PRC68.com
This area (SW Pennsylvania) we do not have galvanic ground distribution. So
when a neutral is damaged all the load is forced back to the ground near
the source. After some time the ground rod is completely corroded and does
not provide a reliable earth sink.
At this point there is no earth, and
Sorry, Brooke-I was not clear. I meant to not connect anything to
neutral at all, but rather to depend on the ground connection already
made in the equipment for the low side of the signal, rather than a 1
meg to neutral at the plug. Sorry.
Don
Brooke Clarke
Hi Don:
Not a good idea. There are
On Thu, 24 Nov 2011 09:37:33 -0700
Robert Darlington rdarling...@gmail.com wrote:
I've done this but don't remember the detail on the wiring. The data sheet
made it clear though. One thing I did notice is that the oscillator
seemed to power the chip! If I were doing it again I'd probably
On Thu, 24 Nov 2011 12:05:13 -0700
Kevin Rosenberg ke...@rosenberg.net wrote:
Since frequency reference sine wave can exceed Vdd, you want to current
limit the external clock. For example, an unterminated TBolt puts out 0-7V
Pk-Pk. Atmel, in an app note where they hook up the pins of an AVR
On Nov 25, 2011, at 1:17 AM, Attila Kinali wrote:
Using the protection diodes as part of the circuit is bad design practice.
In general, I agree completely, Further, I think of operating outside
of the datasheet may result in any manner of unspecified behavior. Basically,
results while operating
On Fri, 25 Nov 2011 02:02:04 -0700
Kevin Rosenberg ke...@rosenberg.net wrote:
In this case, the use of the protection diode and the 1 ma limit
comes directly from the manufacturer Atmel's App Note AVR182 [1].
That said, I'm cautious even when the manufacturer in an App Note
says it's okay,
:14
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Clocking a PIC16F628A from a
Rubidium Standard
On Fri, 25 Nov 2011 02:02:04 -0700
Kevin Rosenberg ke...@rosenberg.net wrote:
In this case, the use of the protection diode and the 1 ma
limit comes
On Fri, Nov 25, 2011 at 12:17 AM, Attila Kinali att...@kinali.ch wrote:
On Thu, 24 Nov 2011 12:05:13 -0700
Kevin Rosenberg ke...@rosenberg.net wrote:
Since frequency reference sine wave can exceed Vdd, you want to current
limit the external clock. For example, an unterminated TBolt puts
distant capacitive loading.
Robert G8RPI.
From: Attila Kinali att...@kinali.ch
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, 25 November 2011, 8:17
Subject: Re: [time-nuts] Clocking a PIC16F628A from a Rubidium Standard
.
From: Attila Kinali att...@kinali.ch
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Friday, 25 November 2011, 8:17
Subject: Re: [time-nuts] Clocking a PIC16F628A from a Rubidium Standard
On Thu, 24 Nov 2011 12:05:13 -0700
Kevin Rosenberg ke
Greetings all,
I have an Efratom 101 frequency standard with a 10 MHz TTL otput. I want to
use this to clock a PIC 16F628A so I can make a frequency counter with a
resolution of 1 Hz. I am going to use the design by EI9GQ here
http://homepage.eircom.net/~ei9gq/counter.html . What I need to know
On Thu, 24 Nov 2011 14:41:24 +
Stephen Farthing squir...@gmail.com wrote:
I have an Efratom 101 frequency standard with a 10 MHz TTL otput. I want to
use this to clock a PIC 16F628A so I can make a frequency counter with a
resolution of 1 Hz. I am going to use the design by EI9GQ here
I've done this but don't remember the detail on the wiring. The data sheet
made it clear though. One thing I did notice is that the oscillator
seemed to power the chip! If I were doing it again I'd probably use some
kind of powered buffer on the oscillator input so that when I power down
the
On Nov 24, 2011, at 7:50 AM, Attila Kinali wrote:
Have a look at the PIC 16F628 data sheet, it will tell you the requirements
for the clock input and there should be circuit for external clock signal
listed. If it's not in the datasheet, it should be in an appnote.
Usually, chips accept
One thing I did notice is that the oscillator seemed to power the chip! If
I were doing it again I'd probably use some kind of powered buffer on the
oscillator input so that when I power down the circuit it actually stops.
That's a reasonably common problem. Occasionally it's a feature.
I have an Efratom 101 frequency standard with a 10 MHz TTL otput. I want to
use this to clock a PIC 16F628A so I can make a frequency counter with a
resolution of 1 Hz. I am going to use the design by EI9GQ here http://
homepage.eircom.net/~ei9gq/counter.html . What I need to know is how i
Stephen,
As well as limiting the input voltage swing into the PIC with a ~2k2 resistor,
add an additional 4k7 or 10k resistor (AOT) across the PIC's Vcc rail to
ground. This swamps the rectified DC produced by the input drive signal when
the PIC DC supply is removed.
I've used /tvb's PIC
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