This might be a dumb question, but is there such thing as a DC variac? I've got an AC one, but I'd like a piece of equipment that can give me DC up +/- a few hundred volts. Is this something to build (I'm thinking a standard power supply configuration but then some kind of setup for at least stepping the voltage up and down, if not a continuous "dialing" possibility).
Thanks.
Thanks.
Flying pig
Sorry. There isn't a simple DC equivalent. You have two options:
Use a variac to feed a 300V transformer/rectifier/smoothing combination. Because second-hand variacs are quite cheap, this can be a very good solution, especially when you want >100mA.
Buy/build a variable regulator that can be adjusted from 0V to 300V. This is seriously expensive (and fragile if it uses silicon)...
Good luck.
Sorry. There isn't a simple DC equivalent. You have two options:
Use a variac to feed a 300V transformer/rectifier/smoothing combination. Because second-hand variacs are quite cheap, this can be a very good solution, especially when you want >100mA.
Buy/build a variable regulator that can be adjusted from 0V to 300V. This is seriously expensive (and fragile if it uses silicon)...
Good luck.
Hey JLG,
I see you're in Youngstown... I'm in Paris Township, just south of Newton Falls (a little west of youngstown).
Small world.
I see you're in Youngstown... I'm in Paris Township, just south of Newton Falls (a little west of youngstown).
Small world.
VARIAC
Hi,
As the name suggest VARI-AC,these are for AC adjustment.
However,depending on your current requirements a rheostat can be used for DC adjustment as long as you can find a suitable wattaged one.
And no,these don't come cheap.
Ciao,😉
Hi,
As the name suggest VARI-AC,these are for AC adjustment.
However,depending on your current requirements a rheostat can be used for DC adjustment as long as you can find a suitable wattaged one.
And no,these don't come cheap.
Ciao,😉
ahh vari-AC
>As the name suggest VARI-AC,these are for AC adjustment.
I seeee. I thought it was just a catchy name for a variable transformer device. "Varidc" doesn't roll of the tongue very easily.
>As the name suggest VARI-AC,these are for AC adjustment.
I seeee. I thought it was just a catchy name for a variable transformer device. "Varidc" doesn't roll of the tongue very easily.
Re:ahh vari-AC
Hi,
Yep.That's it.
And you want an explanation of the word rheostat too,don't you?
Cheers,😉
Hi,
Yep.That's it.
And you want an explanation of the word rheostat too,don't you?
Cheers,😉
well duh
duh, everyone KNOWS it's merely a contrivance for adjusting or regulating the strength of electrical currents, operating usually by the intercalation of resistance which can be varied at will.
or, at least, that's what "wheatstone" had to say about the matter.
duh, everyone KNOWS it's merely a contrivance for adjusting or regulating the strength of electrical currents, operating usually by the intercalation of resistance which can be varied at will.
or, at least, that's what "wheatstone" had to say about the matter.
origin of 'rheostat'
etymologically, though, all i get is something about standing still (stat). is the "rhe" for adjusting? ("o" is just the connective, or so I recall from my Greek etymology days)
etymologically, though, all i get is something about standing still (stat). is the "rhe" for adjusting? ("o" is just the connective, or so I recall from my Greek etymology days)
wheat and bread.
Hi,
Sorry,I was toying a bit with your head.
RHEO-STATOR.
Now both words come from the ancient Greek language although I can't remember what etymological origin *rheo* has,stator obviously means a stationary element.
In essence it is a huge wirewound linear pot or a pot composed of various resistive laminations controlled by a rotary element.
Cheers,😉
Hi,
Sorry,I was toying a bit with your head.
RHEO-STATOR.
Now both words come from the ancient Greek language although I can't remember what etymological origin *rheo* has,stator obviously means a stationary element.
In essence it is a huge wirewound linear pot or a pot composed of various resistive laminations controlled by a rotary element.
Cheers,😉
Re: Re:ahh vari-AC
Absolutely. Teasing animals is cruel. Full etymology required, please.
fdegrove said:And you want an explanation of the word rheostat too,don't you?
Cheers,😉
Absolutely. Teasing animals is cruel. Full etymology required, please.
drop some acid?
speaking of toying with one's head, theoretically, could you get a stack of say 100 6v lead acid batteries in series with some kind of stepped switching system that taps 1, 2, 3, 4, etc. of the batteries? so then you have up to 600/630 vdc in 6.3 volt increments. alternatively, one could use larger units (12, 24). and of course this would be heavy, expensive, and hardly worth doing in real life. but hmmm.
speaking of toying with one's head, theoretically, could you get a stack of say 100 6v lead acid batteries in series with some kind of stepped switching system that taps 1, 2, 3, 4, etc. of the batteries? so then you have up to 600/630 vdc in 6.3 volt increments. alternatively, one could use larger units (12, 24). and of course this would be heavy, expensive, and hardly worth doing in real life. but hmmm.
OOPS
Hi,
Since you asked:
rheos "a flowing, stream"
statos : standing,not moving,remaining stationary.
Cheers,😉
Hi,
Since you asked:
rheos "a flowing, stream"
statos : standing,not moving,remaining stationary.
Cheers,😉
Re: drop some acid?
Someone on rec.audio.tubes beat ya to it (the idea). Think it was jim or so...(if you know RAT, you know jim, and you know this figures 😉 )
One thing's for sure, you'd have no problem with regulation nor filtering 🙂
Tim
jlg4104 said:
Someone on rec.audio.tubes beat ya to it (the idea). Think it was jim or so...(if you know RAT, you know jim, and you know this figures 😉 )
One thing's for sure, you'd have no problem with regulation nor filtering 🙂
Tim
amp hours, dc, and your power tool
ok, lead acid batteries come in a variety of (milli)amp-hour configurations, panasonic's 65 aH being the highest for a 12-volter that I could find (and costing $123). now here's a bit from a piece on power tools:
"Because most of us demand a lot from our cordless tools, a 12v tool will always outperform a 9.6v, regardless of the amp-hour rating. And there's a drawback to higher amp-hour batteries: the higher the amp hours, the shorter the life cycle (total amount of charges per battery) because there's less fluid in the cells.
I also tested the batteries. I found that 2.6ah 12v batteries didn't drive as many screws as 2.0 ah 12v batteries -- same size screws, same 2x4 studs. So much for higher technology."
Now I know power tools are not audio components, but they both use the same stuff. any thoughts?
ok, lead acid batteries come in a variety of (milli)amp-hour configurations, panasonic's 65 aH being the highest for a 12-volter that I could find (and costing $123). now here's a bit from a piece on power tools:
"Because most of us demand a lot from our cordless tools, a 12v tool will always outperform a 9.6v, regardless of the amp-hour rating. And there's a drawback to higher amp-hour batteries: the higher the amp hours, the shorter the life cycle (total amount of charges per battery) because there's less fluid in the cells.
I also tested the batteries. I found that 2.6ah 12v batteries didn't drive as many screws as 2.0 ah 12v batteries -- same size screws, same 2x4 studs. So much for higher technology."
Now I know power tools are not audio components, but they both use the same stuff. any thoughts?
i have in mind...
... a puzzle about what amp-hour rating one should go with if stacking up a whole bunch of lead-acid batteries to use as an occasional variable DC supply in the configuration we discussed before. they go from 1.3 up to 63 or aH, or something like that. I guess the current i'm drawing of course is a factor, but i was wondering what bearing the power-tool quote might have on things.
anyway the expense is kind of prohibitive. but electricity is fun.
... a puzzle about what amp-hour rating one should go with if stacking up a whole bunch of lead-acid batteries to use as an occasional variable DC supply in the configuration we discussed before. they go from 1.3 up to 63 or aH, or something like that. I guess the current i'm drawing of course is a factor, but i was wondering what bearing the power-tool quote might have on things.
anyway the expense is kind of prohibitive. but electricity is fun.
Some enlightenment?
Couldn't a full-wave bridge be fed from the variac and some sort of fixed cap and variable inductor be used for smoothing?
Couldn't a full-wave bridge be fed from the variac and some sort of fixed cap and variable inductor be used for smoothing?
rectification and filtering
sure, but i was just originally wondering about a pure, unadulterated variable DC possibility. it was also mainly just something i was wondering about-- i had no idea if a variable DC animal even existed. apparently they do for low voltages (car system stuff) but not for highs without paying a whole lot of money.
sure, but i was just originally wondering about a pure, unadulterated variable DC possibility. it was also mainly just something i was wondering about-- i had no idea if a variable DC animal even existed. apparently they do for low voltages (car system stuff) but not for highs without paying a whole lot of money.
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