+12V solid line or dotted line ???

[gary350]

Look at the pictures it says, 12V but it says nothing about AC or DC. It has 2 lines, 1 dotted line and 1 solid line. I have seen this before. Does that mean this thing is both 12vac and 12vdc?

OH...yes this things is called a Adaptor NOT a Transformer. I know there is a transformer inside. Few people on earth know what a transformers is these days.

I bought a nice set of $1 yard sale computer speakers with tone, base, treb, volume, with no "Adaptor", I need one. I already have this exact same set of speakers on my computer, wife needs new speakers on her computer.

**broken link removed**

 

[Inquisitive]

It is 120 Vac to 12+ Vdc @ 1250 mA

The tiny illustration just above the Made in China indicates that the center of the plug is (+) positive and the outer part of the plug is (-) negative.

 

[JimB]

It has 2 lines, 1 dotted line and 1 solid line. I have seen this before. Does that mean this thing is both 12vac and 12vdc?

It means that it is DC.

If it was AC there would be a squiggly sine wave instead of the lines.

JimB

 

[Tony Stewart]

the symbols indicates DC and polarity
+12V
__ centre
- - - ring (shield)

 

[MikeMl]

the symbols indicates DC and polarity
+12V
__ centre
- - - ring (shield)

I have have a box of ~ 30 of various sizes and voltages. None of them show:
-----
___ (dashes over solid bar)

Some show +(o- and others show -(o+ for the polarity of the coaxial plug.

 

[Pommie]

Does it really input over 60 watts and output just 15? It must get mightily warm.

Mike.

 

[Reloadron]

I have a pile of the creatures. Some are actually SMPS supplies. It's like a smorgasbord. Some show the line and dashes and some don't, some indicate the polarity and some don't. Gee, meters are a wonderful tool.

Ron

 

[Tony Stewart]

I got this from Value Village for $10 with speakers and Amp included.

Does it really input over 60 watts and output just 15? It must get mightily warm.

Mike.

input current is normally to include for Fuse or breaker ratings , in this case reactive current not dissipated power.
i.e. if you had 20 of these devices on a breaker the rating would be ~16A

 

[gary350]

What is SMPS?

My adaptor for the other set of identical speakers = plastic box with transformer and rectifier appears to have no filter caps inside the box my meter reads 12.2 VDC and 26.1 VAC. This is not making sense? I need to take speakers apart to see what is inside and get a meter reading there.

In my collectors of adaptors I found 1 that is 12 vac 1250ma a rectifier will make that be 1.414 x 12 = 17 vdc.

The yard sale speakers came with no adaptor, sooner or later I might find one or I could build something that works.

 

[Tony Stewart]

It says on the photo switching power supply , not an unregulated brick like most.

Switched Mode Power Supply. SMPS i.e. buck or boost etc.

 

[audioguru]

I looked at 4 of my AC-DC adapters. The heavy ones with 60Hz transformers inside are pretty big without the solid and dotted lines. The SMPS one has a solid and dotted line and is small and lightweight because a Switched Mode Power Supply (see the SMPS letters?) rectifies and filters the mains, then the high DC voltage powers a high frequency power oscillator that drives a small lightweight high frequency transformer that has a tiny ferrite core. Then the high frequency output from the transformer is rectified and filtered with a small high frequency capacitor.

I bought some small name-brand 5V/2A SMPS from an electronic parts liquidation store for $1.50 each. They were made for dial-up modems. They have a trimpot inside so that the output voltage can be adjusted up to 36V I think. The output voltage is regulated.