SMPS v Linear PS

[Musicmanager]

That's what the man said !!

 

[KeepItSimpleStupid]

The linear supply will likely have sinusoidal ripple at 1x or 2x the power line frequency. So, look at the supply witch your scope AC coupled while measuring DC.

The resistance of the input terminals is a good first clue.

Some are AC. some just unfiltered DC and some are regulated DC and some are SMPS.

 

[Nigel Goodwin]

The linear supply will likely have sinusoidal ripple at 1x or 2x the power line frequency.

Just to be more accurate, it won't be anything like sinusoidal, more of a saw tooth/triangle.

 

[Musicmanager]

Morning NG .. ..

That's kinda disappointing .. .. I was hoping for raspberry!

S


Joking apart, whilst the information is always very useful, I have to say to everyone I have settled the issue successfully now .. S

 

[dr pepper]

If your ears still work well unlike mine, sticking your ear up to a linear wall wart you can hear the 50hz bzzz.

A smps can be electrically quiet, however due to the fact a lot of them are made to a price electrical noise if often greater.

 

[Musicmanager]

Hi Dr P

LOL .. ..

If your ears still work well

Unfortunately, blind in both of them !

I've found the most reliable test is the weight .. .. I've been through a box of wall warts collected over time and the linears are significantly heavier - transformer tonnage ..

Also, I'd find the linear bzzz difficult to distinguish from the 5ohz hum from my zimmer frame

Good to hear from you ..

S

 

[Nigel Goodwin]

Unfortunately, blind in both of them !

Not to mention having to bend down low to stick your ear against the socket on the wall

As you say, weight is the obvious and easy way, and measuring the primary resistance is extra confirmation.

 

[KeepItSimpleStupid]

Not to mention having to bend down low to stick your ear against the socket on the wall

You might. I'd use an extension cord. Bring it to the ear.

 

[Nigel Goodwin]

You might. I'd use an extension cord. Bring it to the ear.

So would I (hence the smiley), if there was any reason to do such a thing at all - but simply picking one up tells you instantly if it's linear or SM.

 

[KeepItSimpleStupid]

I know. Remember when the quality of audio amplifiers (valve days) depended on the weight? The heavier the amp, generally the better the amplifier?

 

[Musicmanager]

Huh !

There's only you and I old enough to remember that Kiss !

S


Edit: As the actress said to the Bishop !

 

[dr pepper]

Maybe, however I have a small collection of valve radio's and a couple of telly's.
I know the diffrence between a triode and a pentagrid.

 

[Musicmanager]

Hi Dr P

I know the diffrence between a triode and a pentagrid.

I only ever had a two wheeled bike, but I used to draw pictures with one of them other things !

S