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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Over Voltage / Amperage DC power converter
I have a non mission critical device (a "Super Bark Free" ultra sonic
dog anti-bark trainer) that as an alternative to battery power calls for a 200mA 6V DC power converter. I am wondering if I might get away with a higher powered converter. For instance, I have an old PC speaker wall wart DC converter that is 300mA at 9 volts. Will most low power devices like this tolerate a 50% over volt and over amp, or would it likely result in a quick failure of the device? -- Tony Sivori Due to spam, I'm filtering all Google Groups posters. |
#2
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Over Voltage / Amperage DC power converter
"Tony Sivori" wrote in message news I have a non mission critical device (a "Super Bark Free" ultra sonic dog anti-bark trainer) that as an alternative to battery power calls for a 200mA 6V DC power converter. I am wondering if I might get away with a higher powered converter. For instance, I have an old PC speaker wall wart DC converter that is 300mA at 9 volts. Will most low power devices like this tolerate a 50% over volt and over amp, or would it likely result in a quick failure of the device? -- Tony Sivori Due to spam, I'm filtering all Google Groups posters. The current rating of the power supply is unimportant - sort of - as long as it is at least enough. I say "sort of", because it depends on whether or not the supply is regulated. If it is, then it doesn't matter how little, or how much, up to the rated current level, that you draw from it. The voltage will remain at 9v give or take. If the supply is unregulated, then the chances are that it will be rated at 9v nominal, only when it's loaded close to its maximum. At lower currents, the voltage could well be 20% above that, particularly with small transformers which are notorious for poor load regulation. So the output could easily be up around 11v when lightly loaded. Your bark trainer might well tolerate this, even though it represents getting on for 100% over-voltage, but it is a risk that I don't think I would want to take for the sake of shelling out the small amount that a suitable 6v regulated wall wart would cost. Arfa |
#3
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Over Voltage / Amperage DC power converter
On Sat, 09 May 2009 16:08:51 +0100, Arfa Daily wrote:
The current rating of the power supply is unimportant - sort of - as long as it is at least enough. I say "sort of", because it depends on whether or not the supply is regulated. If it is, then it doesn't matter how little, or how much, up to the rated current level, that you draw from it. The voltage will remain at 9v give or take. If the supply is unregulated, then the chances are that it will be rated at 9v nominal, only when it's loaded close to its maximum. At lower currents, the voltage could well be 20% above that, particularly with small transformers which are notorious for poor load regulation. So the output could easily be up around 11v when lightly loaded. Your bark trainer might well tolerate this, even though it represents getting on for 100% over-voltage, but it is a risk that I don't think I would want to take for the sake of shelling out the small amount that a suitable 6v regulated wall wart would cost. Thanks for that. Sometimes I am too cheap for my own good. -- Tony Sivori Due to spam, I'm filtering all Google Groups posters. |
#4
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Over Voltage / Amperage DC power converter
On May 9, 10:40*am, Tony Sivori wrote:
On Sat, 09 May 2009 16:08:51 +0100, Arfa Daily wrote: The current rating of the power supply is unimportant - sort of - as long as it is at least enough. I say "sort of", because it depends on whether or not the supply is regulated. If it is, then it doesn't matter how little, or how much, up to the rated current level, that you draw from it. The voltage will remain at 9v give or take. If the supply is unregulated, then the chances are that it will be rated at 9v nominal, only when it's loaded close to its maximum. At lower currents, the voltage could well be 20% above that, particularly with small transformers which are notorious for poor load regulation. So the output could easily be up around 11v when lightly loaded. Your bark trainer might well tolerate this, even though it represents getting on for 100% over-voltage, but it is a risk that I don't think I would want to take for the sake of shelling out the small amount that a suitable 6v regulated wall wart would cost. Thanks for that. Sometimes I am too cheap for my own good. -- Tony Sivori Due to spam, I'm filtering all Google Groups posters.- Hide quoted text - - Show quoted text - Any 6 or maybe 7.5 V max supply that is capable of providing at least 200 ma should work, assuming the connector is correct. Most supplies have the center conductor as +, but not all so be sure to check. |
#5
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Over Voltage / Amperage DC power converter
Tony Sivori wrote:
On Sat, 09 May 2009 16:08:51 +0100, Arfa Daily wrote: The current rating of the power supply is unimportant - sort of - as long as it is at least enough. I say "sort of", because it depends on whether or not the supply is regulated. If it is, then it doesn't matter how little, or how much, up to the rated current level, that you draw from it. The voltage will remain at 9v give or take. If the supply is unregulated, then the chances are that it will be rated at 9v nominal, only when it's loaded close to its maximum. At lower currents, the voltage could well be 20% above that, particularly with small transformers which are notorious for poor load regulation. So the output could easily be up around 11v when lightly loaded. Your bark trainer might well tolerate this, even though it represents getting on for 100% over-voltage, but it is a risk that I don't think I would want to take for the sake of shelling out the small amount that a suitable 6v regulated wall wart would cost. Thanks for that. Sometimes I am too cheap for my own good. I have good luck finding wall-warts at certain thrift shops, FWIW. |
#6
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Over Voltage / Amperage DC power converter
I have good luck finding wall-warts at certain thrift shops, FWIW.
Good suggestion. One should take along a multimeter to check their polarity and no-load voltage. |
#7
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Over Voltage / Amperage DC power converter
William Sommerwerck wrote: I have good luck finding wall-warts at certain thrift shops, FWIW. Good suggestion. One should take along a multimeter to check their polarity and no-load voltage. Or just take the whole box home when they are giving them away. -- You can't have a sense of humor, if you have no sense! |
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