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rabiticide wrote:
uh. no sloshing, and i didn't turn it upside down. It seemed pretty
dry. I moved it side to side briskly and neither felt nor heard
anything "slosh". But how else would this be explained? Is H2SO4
pretty viscous?
rK
a bit oily.
I would like to point out that the single supply schematic has a 2200 uFOn Jul 1, 3:07 pm, John Fields <jfie...@austininstruments.com> wrote:
On Tue, 1 Jul 2008 13:30:05 -0700 (PDT), mrdarr...@gmail.com wrote:
On Jul 1, 12:15 pm, John Fields <jfie...@austininstruments.com> wrote:
On Tue, 1 Jul 2008 11:55:35 -0700 (PDT), mrdarr...@gmail.com wrote:
On Jul 1, 11:48 am, Don Bowey <dbo...@comcast.net> wrote:
On 7/1/08 11:30 AM, in article
a1662fad-e0d7-4306-9e20-195abb1e7...@c19g2000prf.googlegroups.com,
"mrdarr...@gmail.com" <mrdarr...@gmail.com> wrote:
I was reading the datasheet for the LM1875
http://www.national.com/ds.cgi/LM/LM1875.pdf
and I noticed that they do have a schematic for a single supply (as
opposed to a +/- supply).
If running on a single supply, does the chip amplifer consume
significant power during quiet tracks?
Would this be pretty much the same as running the amplifier in Class A
mode (vs. Class AB)?
I'm trying to figure out if I really need a +/- power supply, or if I
can just go with a single supply (easier to build).
Thanks,
Michael
The datasheet does have a "Typical Single Supply Operation" schematic.
Have another look.
Yes, that's what I said. There is a schematic. It's on Page 2.
(amused grin)
---
Look at "Supply Current" on page 2 and read: "Power Dissipation and
Heat Sinking" on page 6.
JF
Ah, so apparently the chip does not use more power with a single
supply than with a +/- supply.
Is there any reason why I should NOT use a single supply with this
chip?
---
I don't think so, but try it and see if it works the way you want it
to. If it does you've saved a supply, but if it doesn't it's only
cost you a handful of discretes.
JF
Good point. Thanks.
Michael
Rain water is not clean. It has a nucleus of something and collects crap on"Jonathan Kirwan" <jkirwan@easystreet.com> wrote in message
news:1cui64tp3blo98q3cuekdkbq8mqm64sgnv@4ax.com...
On Mon, 30 Jun 2008 17:06:09 -0700 (PDT), rabiticide
rabiticide@gmail.com> wrote:
It's my motorcycle battery and it's the situation where I need it to
get to this job so I can afford to fix it. I just came off disability
and with $4 to my name I spent $2 on a gallon of distilled water...
Okay. It sounded like that kind of situation. I've been there in my
life, too, so I can feel your pain.
So I am going to try it and see what happens. I will post my
results....
If there doesn't appear to be _any_ sulfuric acid inside, then I don't
hold out much hope here. But best luck, anyway.
Isn't H2SO4 a solid? I don't know - I'm thinking of, like, NaOH which
dissolves in water to make the base.
snip
NaOH is a solid. White, and kind of slippery to the touch. But
sulfuric acid is a liquid. I've used it, before, as part of a double
boiler situation that could achieve the higher melting points I needed
at the time while also providing very, very even heating which was
also necessary for the rocket fuel I was making then.
Jon
Depending on local weather conditions, rain water should woek as well.
--
They can have my command prompt when they pry it from my cold dead
fingers.
Since the LM1875 is inexpensive, you might try using two of them on aI was reading the datasheet for the LM1875
http://www.national.com/ds.cgi/LM/LM1875.pdf
and I noticed that they do have a schematic for a single supply (as
opposed to a +/- supply).
If running on a single supply, does the chip amplifer consume
significant power during quiet tracks?
Would this be pretty much the same as running the amplifier in Class A
mode (vs. Class AB)?
I'm trying to figure out if I really need a +/- power supply, or if I
can just go with a single supply (easier to build).
Thanks,
Michael
As I recall, the animal studies used tiny particles of tungsten. TheIn article <486a101e.590892@news.sysmatrix.net>, NoSpam@daqarta.com
says...
Incandescent bulbs may be hazardous as well: Animal studies of
tungsten shrapnel show that it is a very powerful carcinogen. I don't
know how tungsten dust (which I assume must be inside the envelope
after the filament burns out) would behave in the lungs, but I suspect
the answer would be "not good".
Considering the original quantity of tungsten, and distribution of
'shrapnel', you have a low probability of ingest (stomach/lungs) enough
tungsten to be more than a minor irritant. From recollection it is
difficult to absorb tungsten through skin contact.
If you are going to use an ADC and microprocessor anyway, you mightHi,
I'm looking for a circuit that can read a standard line level audio
signal and output a continous voltage 0-5v proportional to the
amplitude of the input.
This in turn would be read by an ADC/microprocessor to modulate some
flashing lights.
As always - any help is greatly appreciated.
The TO-220 package is used for many devices not just transistors.Is it standard that a TO-220 transistor package is, with the tab up,
with the markings facing you, Base, Collector, Emitter? (for example,
on the TIP31A)
I noticed the TO-92 2N3904 I have is (with the markings facing me) E B
C, and a TO-92 2N2222 data sheet even shows C B E !!!
Michael
You will find some that are not that way.On Jul 2, 10:32 am, "Tom Biasi" <tombiasi...@optonline.net> wrote:
mrdarr...@gmail.com> wrote in message
news:fd4d48c0-8c69-4c14-b6c9-f090c696beaf@i18g2000prn.googlegroups.com...
Is it standard that a TO-220 transistor package is, with the tab up,
with the markings facing you, Base, Collector, Emitter? (for example,
on the TIP31A)
I noticed the TO-92 2N3904 I have is (with the markings facing me) E B
C, and a TO-92 2N2222 data sheet even shows C B E !!!
Michael
The TO-220 package is used for many devices not just transistors.
The pinout is what the data sheet says it is.
Always consult the data sheet if the leads are not marked.
Tom
So does this mean it is NOT standard that a TO-220 *transistor*
package is BCE? (with the markings facing you)
Michael
Try a smaller capacitor e.g. 0.47uFI am experimenting with a relaxation oscillator circuit consisting of
a NE-2 bulb wired parallel to a capacitor and this pair is wired in
series with a resistor and connected across a 150 V DC power source (a
bunch of DC wallwarts connected in series). The resistor is variable
0-1 Meg Ohm, the capacitor is a 1uF electrolytic rated at 160V. I
don't have any capacitors on hand with a higher working voltage.
The circuit seems to work. I can get the bulb to blink around 3 times
a second but I am wanting a higher flash rate and I am not getting
it. Lowering the resistance makes the bulb turn on continuously. I
don't think that the bulb is flashing faster than the eye can
distinguish. I conneded the circuit to an oscilliscope and when the
bulfb is visually flashing I see the RC discharge curve but lowering R
until the bulf truns on continuously pretty much produces a flat line
on the scope.
I was expecting to maybe be able to get around 2-100 hz with a NE-2
relaxation oscillator. Is this possible or am I expecting too much
from this type of circuit? And if so, why?
Any help would be greatly appreciated. Thanks
Since you are going to ADC it anyway, simply capacitivly couple the audioHi,
I'm looking for a circuit that can read a standard line level audio
signal and output a continous voltage 0-5v proportional to the
amplitude of the input.
This in turn would be read by an ADC/microprocessor to modulate some
flashing lights.
As always - any help is greatly appreciated.
Dave
As mentioned above, use a much smaller capacitor. Also, never allow theI am experimenting with a relaxation oscillator circuit consisting of
a NE-2 bulb wired parallel to a capacitor and this pair is wired in
series with a resistor and connected across a 150 V DC power source (a
bunch of DC wallwarts connected in series). The resistor is variable
0-1 Meg Ohm, the capacitor is a 1uF electrolytic rated at 160V. I
don't have any capacitors on hand with a higher working voltage.
The circuit seems to work. I can get the bulb to blink around 3 times
a second but I am wanting a higher flash rate and I am not getting
it. Lowering the resistance makes the bulb turn on continuously. I
don't think that the bulb is flashing faster than the eye can
distinguish. I conneded the circuit to an oscilliscope and when the
bulfb is visually flashing I see the RC discharge curve but lowering R
until the bulf truns on continuously pretty much produces a flat line
on the scope.
I was expecting to maybe be able to get around 2-100 hz with a NE-2
relaxation oscillator. Is this possible or am I expecting too much
from this type of circuit? And if so, why?
Any help would be greatly appreciated. Thanks
That's the definition of negative resistance. When the voltage is high theOn 7/2/08 4:14 PM, in article XXTak.3268$vn7.2496@flpi147.ffdc.sbc.com,
"Bob
Eld" <nsmontassoc@yahoo.com> wrote:
jalbers@bsu.edu> wrote in message
news:2f8acf53-1cda-424c-9073-6706a1eb55ac@k37g2000hsf.googlegroups.com...
I am experimenting with a relaxation oscillator circuit consisting of
a NE-2 bulb wired parallel to a capacitor and this pair is wired in
series with a resistor and connected across a 150 V DC power source (a
bunch of DC wallwarts connected in series). The resistor is variable
0-1 Meg Ohm, the capacitor is a 1uF electrolytic rated at 160V. I
don't have any capacitors on hand with a higher working voltage.
The circuit seems to work. I can get the bulb to blink around 3 times
a second but I am wanting a higher flash rate and I am not getting
it. Lowering the resistance makes the bulb turn on continuously. I
don't think that the bulb is flashing faster than the eye can
distinguish. I conneded the circuit to an oscilliscope and when the
bulfb is visually flashing I see the RC discharge curve but lowering R
until the bulf truns on continuously pretty much produces a flat line
on the scope.
I was expecting to maybe be able to get around 2-100 hz with a NE-2
relaxation oscillator. Is this possible or am I expecting too much
from this type of circuit? And if so, why?
Any help would be greatly appreciated. Thanks
As mentioned above, use a much smaller capacitor. Also, never allow the
resistance to go near zero ohms as this can burn out the NE-2.
The Neon lamp is a negative resistance device. To oscillate it has to
stay
in the negative resistance region. The pot is a positive or normal
resistor.
If it's value is adjusted too low, the overall combination resistance
becomes positive, oscillation stops and the lamp turns full on. That's
what
you are observing. Keep the resistor value high and the capacitor small.
Actually, it's a relaxation oscillator. The lamp is off when the voltage
across the cap is less than the firing voltage (about 67 Volts for a NE2).
When the cap charges to around 67V, the neon ignites and the voltage
across
the cap falls from the low resistance "short" and the cycle of
charge-fire-charge-fire continues, creating the typical sawtooth waveform.
Bob Eld wrote:
Insure that the max peak of the audio signal is within
the ADC range.
Diode clamp it !
Graham
I was expecting to maybe be able to get around 2-100 hz with a NE-2
relaxation oscillator. Is this possible or am I expecting too much
from this type of circuit? And if so, why?
You'd first of all read the specifications of the NE-2. Like a lot of neonI am experimenting with a relaxation oscillator circuit consisting of
a NE-2 bulb wired parallel to a capacitor and this pair is wired in
series with a resistor and connected across a 150 V DC power source (a
bunch of DC wallwarts connected in series). The resistor is variable
0-1 Meg Ohm, the capacitor is a 1uF electrolytic rated at 160V. I
don't have any capacitors on hand with a higher working voltage.
The circuit seems to work. I can get the bulb to blink around 3 times
a second but I am wanting a higher flash rate and I am not getting
it. Lowering the resistance makes the bulb turn on continuously. I
don't think that the bulb is flashing faster than the eye can
distinguish. I conneded the circuit to an oscilliscope and when the
bulfb is visually flashing I see the RC discharge curve but lowering R
until the bulf truns on continuously pretty much produces a flat line
on the scope.
I was expecting to maybe be able to get around 2-100 hz with a NE-2
relaxation oscillator. Is this possible or am I expecting too much
from this type of circuit? And if so, why?
Any help would be greatly appreciated. Thanks
Well, if there is an internal diode from the input to the negative rail, itBob Eld wrote:
"Eeyore" wrote
Bob Eld wrote:
Insure that the max peak of the audio signal is within
the ADC range.
Diode clamp it !
Graham
Yeah you can clamp it but then you loose that and higher values as
peaks.
The whole idea is to convert the peaks to numbers not to clip them off.
You can actively diode clamp. Just don't want to hurt the poor ADC 'just
in
case'. I doubt that for flickering lights, losing anything below say 0x240
will
hurt any
There's really no need to clamp it. The processor input will have
internal
"diodes" that will keep the voltage from exceeding the rail voltage
plus a
little.
A discussion we've had many a time before here !
Likewise the input voltage won't go below ground.
It WON'T ? In what ideal world is this ?
A series resistance should be added to limit the input current and a
shunt
resistance
added to keep the DC level from shifting up due to rectification by
these
clamps.
Uh ?
Graham
I was charging my battery over the weekend and checked it last night
to find the battery dead as a doornail. Upon examination, the battery
is completely dry. I'm guessing it was overcharged and the water
boiled away but it shouldn't've 'cause it's an "automatic battery
charger" that's designed to stop charging when it's done...
So, do I just add distilled H2O? Will that work? I have to walk to the
store 1.5 miles (2.5 km) away and that's a long way to carry 1 gallon
(4? L) of water...
rK
One possible reason it doesn't work with certain transistors is that the twoI built an astable multivibrator with blinking lights (much simpler
than using a 556!), as a test for a circuit that will use a power
transistor (or MOSFET) to pulse a transformer primary for future
experiments.
http://mrdarrett.googlepages.com/blinkenlights002.pdf
Strangely, when I replaced the two 2N3904 transistors with TIP31As,
the circuit would not oscillate unless I briefly disconnected then re-
connected R2 or R3. (I bumped the voltage up from 3V to 6V during
these tests.)
As a work-around, I'm considering just putting the 2N3904s back in,
and connecting the positive end of C2 to the base of a TIP31A.
Inelegant, but I think it will work.
I'm trying to figure out why TIP31As won't work, but it also doesn't
help me any that the TIP31A data sheet does not specify a minimum
V_BE_on.
http://www.st.com/stonline/products/literature/ds/12292/tip31a.pdf
Input?
Michael
I tried simulating various forms of this circuit with both 2N3904 andOn Jul 3, 6:54 pm, "Bob Eld" <nsmontas...@yahoo.com> wrote:
mrdarr...@gmail.com> wrote in message
news:7edf1122-2064-4799-9661-4828c556a5ce@s21g2000prm.googlegroups.com...
I built an astable multivibrator with blinking lights (much simpler
than using a 556!), as a test for a circuit that will use a power
transistor (or MOSFET) to pulse a transformer primary for future
experiments.
http://mrdarrett.googlepages.com/blinkenlights002.pdf
Strangely, when I replaced the two 2N3904 transistors with TIP31As,
the circuit would not oscillate unless I briefly disconnected then re-
connected R2 or R3. (I bumped the voltage up from 3V to 6V during
these tests.)
As a work-around, I'm considering just putting the 2N3904s back in,
and connecting the positive end of C2 to the base of a TIP31A.
Inelegant, but I think it will work.
I'm trying to figure out why TIP31As won't work, but it also doesn't
help me any that the TIP31A data sheet does not specify a minimum
V_BE_on.
http://www.st.com/stonline/products/literature/ds/12292/tip31a.pdf
Input?
Michael
One possible reason it doesn't work with certain transistors is that the
two
transistors come on together and lock up the operation. It fails to
flip-flop. Also, there might not be enough base current for TIP31's
with R2
and R3 at 10K. Lower these resistors. The minimum beta is 25 at 1 amp.
so
you're likely not getting enough current to drive these transistors.
To insure that an astable won't lock up, disconnect R2 and R3 from the
positive rail and connect the junction of the two resistors to the
cathodes
of two diodes. Connect the anodes of the diodes to the anodes of the
LED's,
one on each.
With this arrangement, if the transistors both come on together, the
base
drive is reduced and the circuit will always start.
Just tie the inverting input to the output, unity gain. Three point threeHi All,
Having found dual op amp packages around a fifth the price of
comparable single packages from online distributors, I think i'll go
for the double.
(BTW, I'm using supply of +16, and ground).
I don't want the unused channel drawing current unnecessarily though,
or bouncing the output around.. - If I tie the non-inverting input to
+3.3V, and have a high resistance feedback resistor to the inverting
input (with no other input to that pin), would that be as good as
anything? I figure the output won't have to 'try' very hard to modify
the voltage of an input pin with no other voltages on it..
Am I right?
Thanks..