I am openening a Radio Shack!

c0rbin · 13th March 2003, 01:04 PM

Actually, that's not true. My real post is about those power supplies that come with every little piece of electronic equipment I have owned for the past 10 years.

I need a little help--and since I live in the US, this might be limited to American folks.

You see, the electronic equipment has long since vanished, but I am left with dozens of those power supply chords of the 120, 90 and what-have-you variety.

I am a n00b when it comes to electronics. How can I figure out which of these power supplies are okay to use with electronics I have since acrued?

For example, I have an effects pedal for an electric guitar that has the input for a power supply, but did not come with one.

I have a box full of myriad power supplies.

Batteries being expensive, how do I determine which power supply will be okay to use with the effects pedal so I don't break it?

Is this even a real concern?

13th March 2003, 01:16 PM

Yes, it's very important!

Here's all you need to know.

You need to know the VOLTAGE your device needs, whether it's AC or DC (most are dc but not all!), whether the "tip" is positive or negative, and the amperage the device uses.

The device will be marked with a voltage and the "tip" tiagram. So will the power supplies (if not, you must test them with a voltmeter). Just combine the proper transformer to the proper device.

A complicating issue is the barrel size, the size of the connector itself. A similar barrel size is NOT evidence that you can use a particular supply safely.

After all this, the other thing you need to consider is the amperage supplied by the power supply versus what the device needs. It's fine to have a higher rating on the power supply than the device. The reverse is not fine.

c0rbin · 17th March 2003, 06:03 AM

Thanks, Sundog!

Is there a resource that details these diagrams?

I am a n00b regarding electronics.

17th March 2003, 07:21 AM

Quote:

Originally posted by c0rbin
Thanks, Sundog!

Is there a resource that details these diagrams?

I am a n00b regarding electronics.

The tip diagram is simply a circle with a dot in it. A line will lead from the dot with a + or a - to tell you if the "tip" is positive or negative. Just make sure both diagrams, on the supply and on the device, look the same.

Iconoclast · 18th March 2003, 03:36 AM

c0rbin

Just thought I'd add to sundog's excellent explanation. It is likely that some of the power supplies you have will be "Regulated" power supplies, and some will be "Unregulated".

If you have an unregulated power supplier with a label that says something like "12VDC Unregulated", you have to understand that this supply will only put out 12V when it is connected to some specific predetermined load. Manufacturers often supply unregulated power supplies (because they're cheaper) with pieces equipment that draw a fairly constant current. However, if you hook this supply to a piece of equipment that presents a different load , the supply voltage will be something other than 12V. The only simple way to know what supply voltage you will get with an unknown unregulated power supply is to connect a resistor across it with the same resistance as the input impedance of the device you wish to power and then measure the actual supply voltage under this load, and this will only work with DC power supplies.

If you have a power supply that is labelled as "Regulated", then you can be sure you will get the rated output voltage as long as your equipment doesn't draw more than the rated current (also marked on the PS label) from the supply.

a_unique_person · 18th March 2003, 03:48 AM

Whatever you do, don't just plug one in to see if it works. You could burn out your piece of equipment instantly.

CathodeRay · 25th March 2003, 03:15 PM

c0rbin asked:

Is there a resource that details these diagrams?

A Radio Shack catalog has diagrams and explanations. If you ask for a catalog, and they have any left, they just might give you one. Don't tell them how you are trying to save money or they might make you pay for it.

13th March 2003, 01:04 PM	#1
c0rbin Graduate Poster Join Date: Aug 2001 Posts: 1,806	I am openening a Radio Shack! Actually, that's not true. My real post is about those power supplies that come with every little piece of electronic equipment I have owned for the past 10 years. I need a little help--and since I live in the US, this might be limited to American folks. You see, the electronic equipment has long since vanished, but I am left with dozens of those power supply chords of the 120, 90 and what-have-you variety. I am a n00b when it comes to electronics. How can I figure out which of these power supplies are okay to use with electronics I have since acrued? For example, I have an effects pedal for an electric guitar that has the input for a power supply, but did not come with one. I have a box full of myriad power supplies. Batteries being expensive, how do I determine which power supply will be okay to use with the effects pedal so I don't break it? Is this even a real concern?
c0rbin Graduate Poster Join Date: Aug 2001 Posts: 1,806	__________________ By convention there is color, By convention sweetness, By convention bitterness, But in reality there are atoms and space. --Democritus (c. 400 BCE)

13th March 2003, 01:16 PM	#2
Guest Posts: n/a	Yes, it's very important! Here's all you need to know. You need to know the VOLTAGE your device needs, whether it's AC or DC (most are dc but not all!), whether the "tip" is positive or negative, and the amperage the device uses. The device will be marked with a voltage and the "tip" tiagram. So will the power supplies (if not, you must test them with a voltmeter). Just combine the proper transformer to the proper device. A complicating issue is the barrel size, the size of the connector itself. A similar barrel size is NOT evidence that you can use a particular supply safely. After all this, the other thing you need to consider is the amperage supplied by the power supply versus what the device needs. It's fine to have a higher rating on the power supply than the device. The reverse is not fine.
Guest Posts: n/a

17th March 2003, 06:03 AM	#3
c0rbin Graduate Poster Join Date: Aug 2001 Posts: 1,806	Thanks, Sundog! Is there a resource that details these diagrams? I am a n00b regarding electronics.
c0rbin Graduate Poster Join Date: Aug 2001 Posts: 1,806	__________________ By convention there is color, By convention sweetness, By convention bitterness, But in reality there are atoms and space. --Democritus (c. 400 BCE)

17th March 2003, 07:21 AM	#4
Guest Posts: n/a	Quote: Originally posted by c0rbin Thanks, Sundog! Is there a resource that details these diagrams? I am a n00b regarding electronics. The tip diagram is simply a circle with a dot in it. A line will lead from the dot with a + or a - to tell you if the "tip" is positive or negative. Just make sure both diagrams, on the supply and on the device, look the same.
Guest Posts: n/a

18th March 2003, 03:36 AM	#5
Iconoclast Breaker of Icons Join Date: Sep 2001 Posts: 1,797	c0rbin Just thought I'd add to sundog's excellent explanation. It is likely that some of the power supplies you have will be "Regulated" power supplies, and some will be "Unregulated". If you have an unregulated power supplier with a label that says something like "12VDC Unregulated", you have to understand that this supply will only put out 12V when it is connected to some specific predetermined load. Manufacturers often supply unregulated power supplies (because they're cheaper) with pieces equipment that draw a fairly constant current. However, if you hook this supply to a piece of equipment that presents a different load , the supply voltage will be something other than 12V. The only simple way to know what supply voltage you will get with an unknown unregulated power supply is to connect a resistor across it with the same resistance as the input impedance of the device you wish to power and then measure the actual supply voltage under this load, and this will only work with DC power supplies. If you have a power supply that is labelled as "Regulated", then you can be sure you will get the rated output voltage as long as your equipment doesn't draw more than the rated current (also marked on the PS label) from the supply.
	__________________ A gun is not a weapon Marge, it's a tool, like a butcher knife or a harpoon or... ah... ah... an alligator. You just need more education on the subject. -- Homer Simpson

18th March 2003, 03:48 AM	#6
a_unique_person Director of Hatcheries and Conditioning Join Date: Jul 2002 Location: Mt Disappointment Posts: 33,329	Whatever you do, don't just plug one in to see if it works. You could burn out your piece of equipment instantly.
	__________________ *Continually pushing the boundaries of mediocrity.* Everything is possible, but not everything is probable. For if a man pretend to me that God hath spoken to him supernaturally, and immediately, and I make doubt of it, I cannot easily perceive what argument he can produce to oblige me to believe it. Hobbes

25th March 2003, 03:15 PM	#7
CathodeRay Muse Join Date: Sep 2001 Posts: 837	c0rbin asked: Is there a resource that details these diagrams? A Radio Shack catalog has diagrams and explanations. If you ask for a catalog, and they have any left, they just might give you one. Don't tell them how you are trying to save money or they might make you pay for it.
CathodeRay Muse Join Date: Sep 2001 Posts: 837	__________________ There are two kinds of statistics, the kind you look up and the kind you make up. - RS