what kind of power supply? - Electronic Circuits Projects Diagrams Free

nyeboy2000 · 26th February 2003, 06:26 PM

I am a novice in electroincs with a question about powering two small devices. The specs are 14 amps and 9 volts on one and 9 amps and 15.4 volts on the other. I am guessing that I need an AC to DC power supply. But what do I need to look for when I buy it? Is this range of power standard?

Thanks

**kinjalgp** · 26th February 2003, 06:32 PM

14 and 9 AMPS are very high currents. No doubt you'll get power supply of this rating in the market but be sure of what you are doing because short circuit @ 14 amps can easily cause fire. Are you aware what are those 2 devices?

nyeboy2000 · 26th February 2003, 06:48 PM

when you say 14 amps and 9 amps is a lot, can you give me a comparison to some other items and their currents. For instance, an item with low amps and an item with amps comparable to the 9-14 range

**kinjalgp** · 26th February 2003, 06:50 PM

But before that I would like to know what are those 2 devices which requires such high current.

nyeboy2000 · 26th February 2003, 06:51 PM

sorry about that. They are cooling devices (TEC's)

**kinjalgp** · 26th February 2003, 06:56 PM

When I said high current, I compared it with currents in electronic circuits which are generally of the order of few hunderd milli-amps or sometimes few amps except for power amplifiers. So I was wondering which device is eating so much of current. The best suited power supply would be SMPS as even a compact sized PS can cater considerable amount of current.

nyeboy2000 · 26th February 2003, 07:01 PM

Can you tell me more about SMPS? What is the price range for something like that? What else would I need as far as fuses or other? Also more about any possible safety concerns. I really appreciate all of your info. Thanks.

**kinjalgp** · 26th February 2003, 07:05 PM

SMPS (Switch Mode Power Supply) is a kind of PS similar to one used in computers. As compared to bulky transformers it is quite compact and has many other featutes too like good output regulation, less ripple etc. I don't have idea about pricing of SMPS of 14A and 9A but a computer SMPS will cost you around US $10 which has a 12V output capable of giving 10A and 5V @ 25A.

Regarding safety, a fuse is always good to use whose capacity will depend upon your load current requirements.

nyeboy2000 · 26th February 2003, 07:19 PM

Where can I buy a SMPS and how is it powered? What else will I need to be able to adjust the voltage and current that it outputs?

**kinjalgp** · 26th February 2003, 07:31 PM

Well, a normal computer SMPS is available in any computer hardware shop. It is powered from AC mains 110V/220V. Normally the outputs of SMPS are a fixed voltage but by changing the component values you can vary it.

**kinjalgp** · 26th February 2003, 07:33 PM

See this post if you want to see how a computer's SMPS look like:
http://www.electro-tech-online.com/viewtopic.php?t=730

nyeboy2000 · 26th February 2003, 07:35 PM

Thanks for all the info. I really appreciate it.

Gene · 26th February 2003, 11:39 PM

An example might be a car brake light which pulls about 2 Amps - about the same as a 27" color TV. Of course the TV is AC and that's a different situation but hopefully this will give you an idea of how hot 14 Amps is - please be careful. When you said powering "two small devices" and then said 14 Amps, something didn't sound quite right. Could it maybe have been mA (mili-Amps)?

nyeboy2000 · 27th February 2003, 12:36 AM

It is a cooling device and I have learned that electric heating and cooling devices can use very high current. I would like to learn more about any precautions I should take or any pointers on how I should setup the initial testing of this device. If you have any thoughts on this I would appreciate it.

Gene · 27th February 2003, 02:48 AM

Since you got everyone's attention with the high current thing, you should simply be sure to insulate all connections well. I'm sure you must have heard somewhere that current kills - not voltage; so don't be fooled by the low voltage of this circuit. I think a key word would be, 'respect.' Be aware when the thing is plugged in to the house power as you are working and please know that electrolytic capacitors (which you will surely use) hold power - lots of it - even when the thing is unplugged. Last thought . . . when you are done, put the power supply in a well vented, closed metal box with proper fuses. Good luck!

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26th February 2003, 06:26 PM	(permalink)
nyeboy2000	what kind of power supply? I am a novice in electroincs with a question about powering two small devices. The specs are 14 amps and 9 volts on one and 9 amps and 15.4 volts on the other. I am guessing that I need an AC to DC power supply. But what do I need to look for when I buy it? Is this range of power standard? Thanks

26th February 2003, 06:32 PM	(permalink)
kinjalgp	14 and 9 AMPS are very high currents. No doubt you'll get power supply of this rating in the market but be sure of what you are doing because short circuit @ 14 amps can easily cause fire. Are you aware what are those 2 devices? __________________ "There is no way to peace, peace is the way!"

26th February 2003, 06:48 PM	(permalink)
nyeboy2000	when you say 14 amps and 9 amps is a lot, can you give me a comparison to some other items and their currents. For instance, an item with low amps and an item with amps comparable to the 9-14 range

26th February 2003, 06:50 PM	(permalink)
kinjalgp	But before that I would like to know what are those 2 devices which requires such high current. __________________ "There is no way to peace, peace is the way!"

26th February 2003, 06:51 PM	(permalink)
nyeboy2000	sorry about that. They are cooling devices (TEC's)

26th February 2003, 06:56 PM	(permalink)
kinjalgp	When I said high current, I compared it with currents in electronic circuits which are generally of the order of few hunderd milli-amps or sometimes few amps except for power amplifiers. So I was wondering which device is eating so much of current. The best suited power supply would be SMPS as even a compact sized PS can cater considerable amount of current. __________________ "There is no way to peace, peace is the way!"

26th February 2003, 07:01 PM	(permalink)
nyeboy2000	Can you tell me more about SMPS? What is the price range for something like that? What else would I need as far as fuses or other? Also more about any possible safety concerns. I really appreciate all of your info. Thanks.

26th February 2003, 07:05 PM	(permalink)
kinjalgp	SMPS (Switch Mode Power Supply) is a kind of PS similar to one used in computers. As compared to bulky transformers it is quite compact and has many other featutes too like good output regulation, less ripple etc. I don't have idea about pricing of SMPS of 14A and 9A but a computer SMPS will cost you around US $10 which has a 12V output capable of giving 10A and 5V @ 25A. Regarding safety, a fuse is always good to use whose capacity will depend upon your load current requirements. __________________ "There is no way to peace, peace is the way!"

26th February 2003, 07:19 PM	(permalink)
nyeboy2000	Where can I buy a SMPS and how is it powered? What else will I need to be able to adjust the voltage and current that it outputs?

26th February 2003, 07:31 PM	(permalink)
kinjalgp	Well, a normal computer SMPS is available in any computer hardware shop. It is powered from AC mains 110V/220V. Normally the outputs of SMPS are a fixed voltage but by changing the component values you can vary it. __________________ "There is no way to peace, peace is the way!"

26th February 2003, 07:33 PM	(permalink)
kinjalgp	See this post if you want to see how a computer's SMPS look like: http://www.electro-tech-online.com/viewtopic.php?t=730 __________________ "There is no way to peace, peace is the way!"

26th February 2003, 07:35 PM	(permalink)
nyeboy2000	Thanks for all the info. I really appreciate it.

26th February 2003, 11:39 PM	(permalink)
Gene	An example might be a car brake light which pulls about 2 Amps - about the same as a 27" color TV. Of course the TV is AC and that's a different situation but hopefully this will give you an idea of how hot 14 Amps is - please be careful. When you said powering "two small devices" and then said 14 Amps, something didn't sound quite right. Could it maybe have been mA (mili-Amps)?

27th February 2003, 12:36 AM	(permalink)
nyeboy2000	It is a cooling device and I have learned that electric heating and cooling devices can use very high current. I would like to learn more about any precautions I should take or any pointers on how I should setup the initial testing of this device. If you have any thoughts on this I would appreciate it.

27th February 2003, 02:48 AM	(permalink)
Gene	Since you got everyone's attention with the high current thing, you should simply be sure to insulate all connections well. I'm sure you must have heard somewhere that current kills - not voltage; so don't be fooled by the low voltage of this circuit. I think a key word would be, 'respect.' Be aware when the thing is plugged in to the house power as you are working and please know that electrolytic capacitors (which you will surely use) hold power - lots of it - even when the thing is unplugged. Last thought . . . when you are done, put the power supply in a well vented, closed metal box with proper fuses. Good luck!