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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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dumb question volts/amps - how much is too much?
I've a wall wart which is rated 12 V DC at 1 amp output
The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." |
#2
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dumb question volts/amps - how much is too much?
"pyotr filipivich" wrote in message
... I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. Typically, a device "pulls" what it needs for a lack of a better way of describing it. For instance, a battery capable of powering the space shuttle at 12V could also start my motorcycle, but not the other way around. -- Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com Production Tapping: http://Production-Tapping-Equipment.com/ Flagship Site: http://www.Drill-N-Tap.com VIDEOS: http://www.youtube.com/user/AutoDrill TWITTER: http://twitter.com/AutoDrill FACEBOOK: http://www.facebook.com/AutoDrill V8013-R |
#3
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dumb question volts/amps - how much is too much?
"Joe AutoDrill" on Tue, 26 Apr 2011 14:28:03
-0400 typed in rec.crafts.metalworking the following: "pyotr filipivich" wrote in message .. . I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. Typically, a device "pulls" what it needs for a lack of a better way of describing it. For instance, a battery capable of powering the space shuttle at 12V could also start my motorcycle, but not the other way around. Ah, so "one way of thinking about it"is that - yes, the wall wart can supply up to 1 amp at 12 VDC, but the router is only going to use half an Amp. Thanks. Now to see if I let the magic smoke out. (I've been told by Electrical Engineers, that electrical items run on smoke, and letting the smoke out is what causes them to fail.) tschus pyotr -- pyotr filipivich "Hey, remember when gas was $2.20 a gallon and the unemployment rate was 4.4%? What happened with that? Oh, right, the Democrats won the 2006 Congressional elections." Moe Lane |
#4
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dumb question volts/amps - how much is too much?
pyotr filipivich fired this volley in
: Ah, so "one way of thinking about it"is that - yes, the wall wart can supply up to 1 amp at 12 VDC, but the router is only going to use half an Amp. But the other way of thinking about it is that some Wal Warts are not regulated. If not, and you do not draw something near to their ratings, they may damage the powered equipment by supplying too high a voltage. The little lightweight switching supplies are almost always regulated, but the heavier transformer-based units are often just a transformer, bridge rectifier, and filter capacitor; Their outputs can vary 50% from the rating at full load. LLoyd |
#5
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dumb question volts/amps - how much is too much?
On Tue, 26 Apr 2011 11:24:08 -0700, pyotr filipivich
wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. Yes, more than likely. Make sure that the supply is regulated (just stick a voltmeter across it without a load and read the voltage if you're not sure- it should read 12V within a fraction of a volt). If it weighs only a few ounces, it's a switching supply and they're virtually always regulated. |
#6
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dumb question volts/amps - how much is too much?
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... pyotr filipivich fired this volley in : Ah, so "one way of thinking about it"is that - yes, the wall wart can supply up to 1 amp at 12 VDC, but the router is only going to use half an Amp. But the other way of thinking about it is that some Wal Warts are not regulated. If not, and you do not draw something near to their ratings, they may damage the powered equipment by supplying too high a voltage. The little lightweight switching supplies are almost always regulated, but the heavier transformer-based units are often just a transformer, bridge rectifier, and filter capacitor; Their outputs can vary 50% from the rating at full load. LLoyd It's instructive to see what happens to a wall-wart when you abuse it. If you short the output of one, most of them will fry themselves in an instant from the current overload. I've done that for entertainment when I no longer have use for them. I have too many in my junk box as it is. g I have two of them that did not. The transformers in them must be so pathetically underbuilt that they just buzzed. Most of them are somewhat self-limiting by virtue of extreme transformer inefficiency, but most in my limited experience will not tolerate a direct short. Regarding the motor, if you supply too much voltage, you probably will get a surprise regarding that 1/2 Amp. -- Ed Huntress |
#7
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dumb question volts/amps - how much is too much?
"Ed Huntress" wrote in message ... It's instructive to see what happens to a wall-wart when you abuse it. If you short the output of one, most of them will fry themselves in an instant from the current overload. That's because they are almost always with Underwriters Labs as being a "current limiting device" and as such they are actually designed to fry in an overcurrent situation--and the main reason they are so prevalent these days is exactly because this...IE, in many situations it allows manufacturers to circumvent agency certification so long as the device is sold along with a "listed power supply"....essentially making it faster, easier and less costly for manufacturers to bring new electronic items to the marketplace.. That said, beware of "counterfiet UL stickers", items imported from Communist China being notorious for this particular consumer fraud. -- |
#8
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dumb question volts/amps - how much is too much?
On Apr 26, 3:17*pm, "Ed Huntress" wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in messagenews:Xns9ED399F9754E7lloydspmindspringcom@2 16.168.3.70... pyotr filipivich fired this volley in : * * *Ah, so "one way of thinking about it"is that - yes, the wall wart can supply up to 1 amp at 12 VDC, but the router is only going to use half an Amp. But the other way of thinking about it is that some Wal Warts are not regulated. *If not, and you do not draw something near to their ratings, they may damage the powered equipment by supplying too high a voltage. The little lightweight switching supplies are almost always regulated, but the heavier transformer-based units are often just a transformer, bridge rectifier, and filter capacitor; *Their outputs can vary 50% from the rating at full load. LLoyd It's instructive to see what happens to a wall-wart when you abuse it. If you short the output of one, most of them will fry themselves in an instant from the current overload. I've done that for entertainment when I no longer have use for them. I have too many in my junk box as it is. g I have two of them that did not. The transformers in them must be so pathetically underbuilt that they just buzzed. Most of them are somewhat self-limiting by virtue of extreme transformer inefficiency, but most in my limited experience will not tolerate a direct short. Regarding the motor, if you supply too much voltage, you probably will get a surprise regarding that 1/2 Amp. -- Ed Huntress- Boy, Ed, you sure are easily entertained. Many of these things have fusible links under the first layer of tape in the transformer, others have "polyfuse" type circuit interruptors. Would you prefer, perhaps, that they supply unlimited current and just catch fire when you short them? BTW, regarding the original question: Yes, a properly working device will draw only what current it needs from your 12V supply (assuming it's putting out something near 12V), but the designers sometimes rely on the overcurrent protection built into the supply rather than spending the extra $0.25 to put a fuse in the router. So, if you had a fault situation in the device and it was connected to a larger than expected supply, you *could* have a fire. In reality, it's unlikely; at the currents your talking about (0.5A vs 1.0A) it's virtually impossible, but I've seen installations which have large numbers of consumer-grade devices connected to a single large supply, and that sort of thing could be a problem. |
#9
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dumb question volts/amps - how much is too much?
"rangerssuck" wrote in message ... On Apr 26, 3:17 pm, "Ed Huntress" wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in messagenews:Xns9ED399F9754E7lloydspmindspringcom@2 16.168.3.70... pyotr filipivich fired this volley in : Ah, so "one way of thinking about it"is that - yes, the wall wart can supply up to 1 amp at 12 VDC, but the router is only going to use half an Amp. But the other way of thinking about it is that some Wal Warts are not regulated. If not, and you do not draw something near to their ratings, they may damage the powered equipment by supplying too high a voltage. The little lightweight switching supplies are almost always regulated, but the heavier transformer-based units are often just a transformer, bridge rectifier, and filter capacitor; Their outputs can vary 50% from the rating at full load. LLoyd It's instructive to see what happens to a wall-wart when you abuse it. If you short the output of one, most of them will fry themselves in an instant from the current overload. I've done that for entertainment when I no longer have use for them. I have too many in my junk box as it is. g I have two of them that did not. The transformers in them must be so pathetically underbuilt that they just buzzed. Most of them are somewhat self-limiting by virtue of extreme transformer inefficiency, but most in my limited experience will not tolerate a direct short. Regarding the motor, if you supply too much voltage, you probably will get a surprise regarding that 1/2 Amp. -- Ed Huntress- Boy, Ed, you sure are easily entertained. I used to tear the wings off of flies, until I discovered RCM. Many of these things have fusible links under the first layer of tape in the transformer, others have "polyfuse" type circuit interruptors. Would you prefer, perhaps, that they supply unlimited current and just catch fire when you short them? It would be fun to watch. d8-) BTW, regarding the original question: Yes, a properly working device will draw only what current it needs from your 12V supply (assuming it's putting out something near 12V), but the designers sometimes rely on the overcurrent protection built into the supply rather than spending the extra $0.25 to put a fuse in the router. So, if you had a fault situation in the device and it was connected to a larger than expected supply, you *could* have a fire. In reality, it's unlikely; at the currents your talking about (0.5A vs 1.0A) it's virtually impossible, but I've seen installations which have large numbers of consumer-grade devices connected to a single large supply, and that sort of thing could be a problem. |
#10
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dumb question volts/amps - how much is too much?
pyotr filipivich wrote:
I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. More or less correct. However I'm betting that the router doesn't even need 12 volts. Probably that has a LOT of overhead in it. Most electronics out there use around 5-6 volts. The extra allows for voltage sags, spikes due to other items starting up. If you opened the router the first items in the power feed will likely be a couple of capacitors and a couple of regulators. Likely a 7805 type with maybe a 7905 if it also has a negative rail. -- Steve W. |
#11
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dumb question volts/amps - how much is too much?
On Tue, 26 Apr 2011 11:24:08 -0700, pyotr filipivich
wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Corret. It will draw what it needs up to the capacity of the wall warts maximum rating. Gunner -- "If I say two plus two is four and a Democrat says two plus two is eight, it's not a partial victory for me when we agree that two plus two is six. " Jonah Goldberg (modified) |
#12
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dumb question volts/amps - how much is too much?
On Tue, 26 Apr 2011 18:13:33 -0400, the renowned "Steve W."
wrote: pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. More or less correct. However I'm betting that the router doesn't even need 12 volts. Probably that has a LOT of overhead in it. Most electronics out there use around 5-6 volts. The extra allows for voltage sags, spikes due to other items starting up. If you opened the router the first items in the power feed will likely be a couple of capacitors and a couple of regulators. Likely a 7805 type with maybe a 7905 if it also has a negative rail. Most routers that I've seen use a switching power supply to knock down an input voltage (5 or 12VDC) to 3.3VDC and lower for most of the juice. Here's a typical one-chip switch (not router) http://www.marvell.com/products/swit..._datasheet.pdf Page 138 has the current requirements.. up to 22mA typical at 3.3V = 73mW up to 330 or so mA typical at 2.5V = 825mW up to 150mA typical at 1.5V = 225mW plus more for power supply losses, LEDs etc. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
#13
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dumb question volts/amps - how much is too much?
On 2011-04-26, Steve W. wrote:
pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. More or less correct. However I'm betting that the router doesn't even need 12 volts. Probably that has a LOT of overhead in it. Most electronics out there use around 5-6 volts. The extra allows for voltage sags, spikes due to other items starting up. If you opened the router the first items in the power feed will likely be a couple of capacitors and a couple of regulators. Likely a 7805 type with maybe a 7905 if it also has a negative rail. Most wall warts are not regulated and are meant to produce proper voltage at the operating current. They may supply higher voltage at lower current. i |
#14
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dumb question volts/amps - how much is too much?
Ignoramus7326 fired this volley in
: Most wall warts are not regulated and are meant to produce proper That may have been true in the past, but more and more we're seeing the switching variety, now that they've included the switching transistors on the control chips. Usually, now, you'll see electronics powered by switchers, and DC motor- driven appliances by the dumb type. But with the cost and manual labor associated with assembling a transformer, I expect more will become switchers, even for the motor devices. LLoyd |
#15
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dumb question volts/amps - how much is too much?
"Steve W." on Tue, 26 Apr 2011 18:13:33 -0400
typed in rec.crafts.metalworking the following: pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. More or less correct. However I'm betting that the router doesn't even need 12 volts. Probably "Probably" - but all I know is what I can decipher off the sticker. B-) ...that has a LOT of overhead in it. Most electronics out there use around 5-6 volts. The extra allows for voltage sags, spikes due to other items starting up. If you opened the router the first items in the power feed will likely be a couple of capacitors and a couple of regulators. Likely a 7805 type with maybe a 7905 if it also has a negative rail. -- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough! |
#16
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dumb question volts/amps - how much is too much?
On Tue, 26 Apr 2011 15:17:33 -0400, "Ed Huntress"
wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message .3.70... pyotr filipivich fired this volley in : Ah, so "one way of thinking about it"is that - yes, the wall wart can supply up to 1 amp at 12 VDC, but the router is only going to use half an Amp. But the other way of thinking about it is that some Wal Warts are not regulated. If not, and you do not draw something near to their ratings, they may damage the powered equipment by supplying too high a voltage. The little lightweight switching supplies are almost always regulated, but the heavier transformer-based units are often just a transformer, bridge rectifier, and filter capacitor; Their outputs can vary 50% from the rating at full load. LLoyd It's instructive to see what happens to a wall-wart when you abuse it. If you short the output of one, most of them will fry themselves in an instant from the current overload. I've done that for entertainment when I no longer have use for them. I have too many in my junk box as it is. g I have two of them that did not. The transformers in them must be so pathetically underbuilt that they just buzzed. Most of them are somewhat self-limiting by virtue of extreme transformer inefficiency, but most in my limited experience will not tolerate a direct short. Regarding the motor, if you supply too much voltage, you probably will get a surprise regarding that 1/2 Amp. No motor in a router - not in the computer type anyway - and a 12 volt 1/2 amp Motor type router is only 6 watts, or roughly 1/100 hp. |
#17
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dumb question volts/amps - how much is too much?
pyotr filipivich wrote:
I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Supply verses demand. The wart can supply an amp. The router only draws 1/2 amp. Live is good. If the draw approaches the supply's capability things get if-ier. At some point the draw will pull the voltage down below spec. At some other point that will really suck. -- Richard Lamb http://www.home.earthlink.net/~cavelamb http://www.home.earthlink.net/~sv_temptress |
#18
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dumb question volts/amps - how much is too much?
Ed Huntress wrote:
It's instructive to see what happens to a wall-wart when you abuse it. If you short the output of one, most of them will fry themselves in an instant from the current overload. I've done that for entertainment when I no longer have use for them. I have too many in my junk box as it is. g I have two of them that did not. The transformers in them must be so pathetically underbuilt that they just buzzed. Most of them are somewhat self-limiting by virtue of extreme transformer inefficiency, but most in my limited experience will not tolerate a direct short. Regarding the motor, if you supply too much voltage, you probably will get a surprise regarding that 1/2 Amp. Letting the magic smpke out causes the house to smell bad! -- Richard Lamb http://www.home.earthlink.net/~cavelamb http://www.home.earthlink.net/~sv_temptress |
#19
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dumb question volts/amps - how much is too much?
Think of voltage as the Pressure.
Current is the flow based on the pressure and the resistance to that pressure. In other words - the voltage sets the current flow on a load. The router uses 12v and has a resistance (simple terms here) that draws 1/2 an amp - so the wall wort runs in idle. you might have a faster starting speed - that might not be good. It might not matter. Start current is higher than run current. The wart can handle the higher currents when starting and when loaded. Martin On 4/26/2011 1:24 PM, pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." |
#20
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dumb question volts/amps - how much is too much?
pyotr filipivich writes:
I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. Yes, that's correct. -- It's time to try defying gravity |
#21
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dumb question volts/amps - how much is too much?
On Tue, 26 Apr 2011 17:22:19 -0700, pyotr filipivich
wrote: "Steve W." on Tue, 26 Apr 2011 18:13:33 -0400 typed in rec.crafts.metalworking the following: pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. More or less correct. However I'm betting that the router doesn't even need 12 volts. Probably "Probably" - but all I know is what I can decipher off the sticker. B-) ...that has a LOT of overhead in it. Most electronics out there use around 5-6 volts. The extra allows for voltage sags, spikes due to other items starting up. If you opened the router the first items in the power feed will likely be a couple of capacitors and a couple of regulators. Likely a 7805 type with maybe a 7905 if it also has a negative rail. I've tried a 9 volt power supply on the odd one, and they did NOT work. On others they would likely work. If you have + and - 5 volt rails, from a DC source, a minimum of about 10.7 volts is required.. |
#22
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dumb question volts/amps - how much is too much?
On Tue, 26 Apr 2011 21:52:47 -0500, Martin Eastburn
wrote: Think of voltage as the Pressure. Current is the flow based on the pressure and the resistance to that pressure. In other words - the voltage sets the current flow on a load. The router uses 12v and has a resistance (simple terms here) that draws 1/2 an amp - so the wall wort runs in idle. you might have a faster starting speed - that might not be good. It might not matter. Start current is higher than run current. The wart can handle the higher currents when starting and when loaded. Martin On 4/26/2011 1:24 PM, pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Martin - this router is not a rotary tool - it is a data device. |
#23
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dumb question volts/amps - how much is too much?
Letting the magic smpke out causes the house to smell bad!
Not as bad as the piece of Tupperware my wife "cooked" in the electric oven last night... -- Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com Production Tapping: http://Production-Tapping-Equipment.com/ Flagship Site: http://www.Drill-N-Tap.com VIDEOS: http://www.youtube.com/user/AutoDrill TWITTER: http://twitter.com/AutoDrill FACEBOOK: http://www.facebook.com/AutoDrill V8013-R |
#24
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dumb question volts/amps - how much is too much?
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#25
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dumb question volts/amps - how much is too much?
On Tue, 26 Apr 2011 11:24:08 -0700, pyotr filipivich
wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Think of voltage as pressure and current (amps) as flow rate. The flow rate depends on the load or current conducting path available, just as it depends on pipe size, valve setting, etc in a water supply system. A short presents no resistance to flow, like an open water main, so flow rate will be the capacity of the source. Your half-amp load presents resistance to flow such that when supplied with 12 VDC it will draw about 1/2 amp even if the 12 volt source were capable of supplying thousands of amps, just as a faucet might draw one gallon per minute from an 80 psi water main capable of delivering hundreds of GPM to a hydrant. |
#26
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dumb question volts/amps - how much is too much?
On Apr 27, 12:45*pm, Don Foreman
wrote: ... Your half-amp load presents resistance to flow such that when supplied with 12 VDC it will draw about 1/2 amp even if the 12 volt source were capable of supplying thousands of amps, *... True, but as I said above, only if there is no fault in the device. There are some devices that rely on the overcurrent protection in the wall wart. If such a device was powered by an unlimited supply and there was a fault in its circuitry that caused ot to draw lots more current, there could be an exciting event - Ed might find it amusing ;-) |
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dumb question volts/amps - how much is too much?
On Wed, 27 Apr 2011 08:40:30 -0400, "Joe AutoDrill"
wrote: Letting the magic smpke out causes the house to smell bad! Not as bad as the piece of Tupperware my wife "cooked" in the electric oven last night... GAAACKKK!!!! My wife used to use the broiler to store extra pots and pan..and she stuffed in some plastic stuff and not thinking ...turned the oven on to warm it up to baking temps. Fortunately..I keep fire extinguishers everywhere around the house. With a nice BIG CO2 extinguisher near the stove. Nasty nasty nasty smell that took months to go away. Gunner -- "If I say two plus two is four and a Democrat says two plus two is eight, it's not a partial victory for me when we agree that two plus two is six. " Jonah Goldberg (modified) |
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dumb question volts/amps - how much is too much?
Don Foreman on Wed, 27 Apr 2011
11:45:24 -0500 typed in rec.crafts.metalworking the following: On Tue, 26 Apr 2011 11:24:08 -0700, pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Think of voltage as pressure and current (amps) as flow rate. The flow rate depends on the load or current conducting path available, just as it depends on pipe size, valve setting, etc in a water supply system. A short presents no resistance to flow, like an open water main, so flow rate will be the capacity of the source. Your half-amp load presents resistance to flow such that when supplied with 12 VDC it will draw about 1/2 amp even if the 12 volt source were capable of supplying thousands of amps, just as a faucet might draw one gallon per minute from an 80 psi water main capable of delivering hundreds of GPM to a hydrant. Electricity is like water - it has to have a 'flow' out in order for it to 'flow' in. Hence the number of electricians who will work with one hand in their pocket. -- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough! |
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Update dumb question volts/amps - how much is too much?
On Wed, 27 Apr 2011 10:27:51 -0700, pyotr filipivich
wrote: (What I'm trying to do is use the WiFi connection on a laptop for Internet access - to neighbor's WiFi router - and then hook the desk top to the Laptop, so that the Desktop can log-on through the WiFi. Microsoft has no clue as to how that might work, so it figures I must mean I want to set up a wireless router connection and the wizard then blithely completely screws things up. But that is a different rant.) -- http://www.ehow.com/how_2308651_use-...-repeater.html http://reviews.pricegrabber.com/wire...ing/m/2932693/ -- "If I say two plus two is four and a Democrat says two plus two is eight, it's not a partial victory for me when we agree that two plus two is six. " Jonah Goldberg (modified) |
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dumb question volts/amps - how much is too much?
On Wed, 27 Apr 2011 10:27:51 -0700, pyotr filipivich
wrote: Don Foreman on Wed, 27 Apr 2011 11:45:24 -0500 typed in rec.crafts.metalworking the following: On Tue, 26 Apr 2011 11:24:08 -0700, pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Think of voltage as pressure and current (amps) as flow rate. The flow rate depends on the load or current conducting path available, just as it depends on pipe size, valve setting, etc in a water supply system. A short presents no resistance to flow, like an open water main, so flow rate will be the capacity of the source. Your half-amp load presents resistance to flow such that when supplied with 12 VDC it will draw about 1/2 amp even if the 12 volt source were capable of supplying thousands of amps, just as a faucet might draw one gallon per minute from an 80 psi water main capable of delivering hundreds of GPM to a hydrant. Electricity is like water - it has to have a 'flow' out in order for it to 'flow' in. Hence the number of electricians who will work with one hand in their pocket. And power Engineers with both hands in their pockets.. |
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dumb question volts/amps - how much is too much?
pyotr filipivich wrote:
Electricity is like water - it has to have a 'flow' out in order for it to 'flow' in. Hence the number of electricians who will work with one hand in their pocket. Wouldn't that be "hand in YOUR pocket"? -- Richard Lamb http://www.home.earthlink.net/~cavelamb http://www.home.earthlink.net/~sv_temptress |
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dumb question volts/amps - how much is too much?
pyotr filipivich wrote:
Electricity is like water - it has to have a 'flow' out in order for it to 'flow' in. Hence the number of electricians who will work with one hand in their pocket. I like the water pipe analogy, until it comes to "short" circuits and "open" circuits. ;-D Cheers! Rich |
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dumb question volts/amps - how much is too much?
Spehro Pefhany wrote:
On Wed, 27 Apr 2011 10:27:51 -0700, pyotr filipivich Electricity is like water - it has to have a 'flow' out in order for it to 'flow' in. Hence the number of electricians who will work with one hand in their pocket. And power Engineers with both hands in their pockets.. When I was in the USAF, if you were caught wearing any jewelry while working on electronics, even freakin' DOG TAGS, you were subject to disciplinary action. Actually, I was kind of astonished when I learned that a welding arc drops about 20-30 volts. Consequently, I wouldn't even wear a wris****ch while, say, jump-starting a car. I was once helping a buddy jump-start his car - I put the cables on my battery, and he proceeded to start to apply the clamps to his battery - red to black and black to red. I shrieked, "NO!NO!NO!NO!NO!NO!NO!NO!NO!" and luckily stopped him in time. Whew! Cheers! Rich |
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dumb question volts/amps - how much is too much?
rangerssuck wrote:
On Apr 27, 12:45*pm, Don Foreman wrote: ... Your half-amp load presents resistance to flow such that when supplied with 12 VDC it will draw about 1/2 amp even if the 12 volt source were capable of supplying thousands of amps, *... True, but as I said above, only if there is no fault in the device. There are some devices that rely on the overcurrent protection in the wall wart. If such a device was powered by an unlimited supply and there was a fault in its circuitry that caused ot to draw lots more current, there could be an exciting event - Ed might find it amusing ;-) I was kind of surprised to learn that the fuse in the equipment isn't there for the purpose of protecting the equipment - it's there to protect the supply and its wiring from when the equipment fails short. Cheers! Rich |
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dumb question volts/amps - how much is too much?
Gunner Asch wrote:
On Wed, 27 Apr 2011 08:40:30 -0400, "Joe AutoDrill" Letting the magic smpke out causes the house to smell bad! Not as bad as the piece of Tupperware my wife "cooked" in the electric oven last night... GAAACKKK!!!! My wife used to use the broiler to store extra pots and pan..and she stuffed in some plastic stuff and not thinking ...turned the oven on to warm it up to baking temps. Fortunately..I keep fire extinguishers everywhere around the house. With a nice BIG CO2 extinguisher near the stove. Nasty nasty nasty smell that took months to go away. One of the things I worked on when in the USAF was a jamming transmitter with a separate power supply. The power supply was pressurized, to maintain breakdown voltage so that it didn't arc over internally. One day, we got one of the pressurized power supplies in the shop that had blown its selenium rectifiers. Hoo Boy! It cleared the whole building for the rest of the day! Cheers! Rich |
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dumb question volts/amps - how much is too much?
pyotr filipivich wrote:
[question about volts/amps] The only "dumb" question is the one you don't ask. (Unless you ask Mr. Garrison - he says, "There are no stupid questions, only stupid people.") Cheers! Rich the Philosophizer |
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Update dumb question volts/amps - how much is too much?
pyotr filipivich wrote:
Larry Jaques on Wed, 27 Apr 2011 07:01:00 -0700 typed in rec.crafts.metalworking the following: On Tue, 26 Apr 2011 23:48:29 -0400, wrote: On Tue, 26 Apr 2011 21:52:47 -0500, Martin Eastburn wrote: Think of voltage as the Pressure. Current is the flow based on the pressure and the resistance to that pressure. In other words - the voltage sets the current flow on a load. The router uses 12v and has a resistance (simple terms here) that draws 1/2 an amp - so the wall wort runs in idle. you might have a faster starting speed - that might not be good. It might not matter. Start current is higher than run current. The wart can handle the higher currents when starting and when loaded. Martin On 4/26/2011 1:24 PM, pyotr filipivich wrote: I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Martin - this router is not a rotary tool - it is a data device. I was wondering about that in the initial stages of reading the OP's message. g would hardly power a HF mini-Dremel, let alone a real MAN'S router. giggle No, I've got power supplies for those things. Thanks to everybody for the advice. The router "worked" for some values of "worked". But trying to set up an home network which did not kill off the WiFi access in the process ... I had to go back to he restore point. (What I'm trying to do is use the WiFi connection on a laptop for Internet access - to neighbor's WiFi router - and then hook the desk top to the Laptop, so that the Desktop can log-on through the WiFi. Microsoft has no clue as to how that might work, so it figures I must mean I want to set up a wireless router connection and the wizard then blithely completely screws things up. But that is a different rant.) Install Linux; it'll be almost trivial. Good Luck! Rich |
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dumb question volts/amps - how much is too much?
Should have been "stupid listeners" on Usenet...LOL
----------------- "Rich Grise" wrote in message ... pyotr filipivich wrote: [question about volts/amps] The only "dumb" question is the one you don't ask. (Unless you ask Mr. Garrison - he says, "There are no stupid questions, only stupid people.") Cheers! Rich the Philosopher |
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dumb question volts/amps - how much is too much?
"pyotr filipivich" wrote in message ... I've a wall wart which is rated 12 V DC at 1 amp output The router is (I think) expecting 12 VCD at .5 amp. And I correct in assuming that the wall wart will not "over supply" the device - that its rating is essentially the max amperage it will output, while the router is the amount it will draw to function? That seems to make sense, to me. At this hour of the morning. -- pyotr filipivich. Discussing the decline in the US's tech edge, James Niccol once wrote "It used to be that the USA was pretty good at producing stuff teenaged boys could lose a finger or two playing with." Let me guess that you have a D-Link router? My D-links have eaten a number of power supplies until I got a good non-OEM one rated at 2 amps. It'll only draw what it needs but I think it sometimes needs more than the OEM supply can reliably deliver. |
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