How can you tell if a power supply or adaptor is a switching one?

[canidoit]

I just checked a couple of power adaptors that output 18 volts AC and I wanted to know if there are any way of knowing if it is switching.

What exactly is switching on a power adaptor? Does it occur on both AC and DC?

 

[Majestic12]

Switching power supplies do not a have a big and heavy transformer. Mostly you can tell it by the weight. Switching power supplies are mostly very light and small.

 

[robovox]

Switch-mode adapters are generally only used to generate DC. Your 18VAC output adapters likely contain nothing more than a transformer to take the 50/60Hz line voltage down.

 

[canidoit]

Would using a 50hz power adaptor not advisable for a unit that uses 60hz?

I can see that the hz relates to countries, is this correct?

What sort of issues would this cause if you do not match the hz in the units requirements. eg. noise, oscillation, buzz, hum, decrease lifespan, etc.

Is there a hz converter?

 

[gemini86]

The difference between 50 and 60 is so little that most transformers don't care...

 

[canidoit]

The difference between 50 and 60 is so little that most transformers don't care...

Does it affect the sound though?

 

[abechap024]

The difference between 50 and 60 is so little that most transformers don't care...

Does it affect the sound though?

All the power transformer will do is act as galvanic isolation and a convient way to step up step down AC power. Sound it totally irrevelent in this application....and I wouldn't reccomend hooking one up to your speakers to find out! if you look at most (if not all power transformers) they say 50/60hz. Think of it like an audio transformer (cause thats all it is...but bulked up for more power and bandlimited) would a transformer pass a 1k tone as easy as a 2k tone? Most likely.

 

[gemini86]

The difference between 50 and 60 is so little that most transformers don't care...

Does it affect the sound though?

All the power transformer will do is act as galvanic isolation and a convient way to step up step down AC power. Sound it totally irrevelent in this application....and I wouldn't reccomend hooking one up to your speakers to find out! if you look at most (if not all power transformers) they say 50/60hz. Think of it like an audio transformer (cause thats all it is...but bulked up for more power and bandlimited) would a transformer pass a 1k tone as easy as a 2k tone? Most likely.

He speaks the truth!

But the one thing to consider is that all the math done to calculate core size, turns, inductance, etc...all depend on a frequency. Now, when you plug 50hz into a tx made for 60hz(or at least optimized for) you may not get EXACTLY what they advertise... but guess what else, you never get what they advertise anyway. They're very imperfect things.

Most switching PSU's still have transformers in them as well, but they're tiny because the cores operate in the RF range. BUT they also operate on a HUGE scale of frequencies. Like, 75khz-300khz. That's huge compared to 60 vs 50...

Everything little thing changes everything...but, will you notice? nope.

 

[canidoit]

Are there any tests you can do to find out if the power supply is a switcher one?

 

[gemini86]

If you're talking about your ac adapter, than it's not a switcher...

 

[abechap024]

Are there any tests you can do to find out if the power supply is a switcher one?

You could measure the resistance on the 2 prongs you plug into the wall. and then were it comes out. If they are lowish (less than 100ohms) then you can bet its a transformer. Plus, if its stepping down the AC voltage, you would expect the primary (the side that goes into the wall) will have a higher ohm reading than the secondary, as there are more turns of wire.

But I agree with whats been said. if its an AC power adaptor it IS a transformer. You could not Chop the AC signal  (50hz or 60hz) into a high KHZ waveform only to convert it back to a 60hz waveform. That would be crazy when you could pop in a 50 cent transformer to do the same thing better and cheaper.