What's AC/AC Power Adapter?

[eedac]

what the pros or applications for AC/AC adapter??

I just heard this form a salesman and says it is popular in AM receiver....

It seems NOT kinds of SMPS. It looks like linear type adapter: i/p 230VAC to o/p9VAC(500mA).

I want to know that
1) is it just simply a classic linear AC/DC adapter, but removes the rectifier bridge and caps?
2) if so, what the advantages? why?

 

[barry]

I think it's a transformer.

 

[Raza]

The other name of the Transformer is AC/AC adapter. Some times it is a trick of salesmanship for the people who do not understand what it means to make money.

 

[eedac]

Yes, I think it is exactly a transformer.

But I have no idea what the guys need such AC/AC adaptor, and how they claim to works with AM receiver ;(

 

[enjunear]

For small radios, taking the 60 Hz transformer out of the radio means it's lighter and cheaper to produce. It's just a way of decreasing the radio's cost by moving some of the functionality of the system outside the box.

 

[eedac]

To enjunear, thx
If so, they could use AC/DC adaptor, all rectifiers and caps assemblied in adaptor inside. I am pluzzed why they propose "AC-to-AC adaptor"?

 

[Raza]

Yes eedac you right. In that case they could have made money more in providing a separate supply. As I said it is just a trick of salesmanship and has got nothing to do specially with AM Radios. Some times to make things small in size the supply transformers are supplied separately with the equipment, like a Modem or a USB HUB (having its own power supply) etc.

 

[barry]

Manufacturers also use external adapters to avoid having to do safety certification testing. If your product runs off a voltage less than some value (say, 35V) it is exempt from having to be certified. Say a manufacturer makes 20 different USB HUBS and they all use the same adapter. They don't have to certify the hubs, just the adapter; or they can buy the adapter from another mfr who has to certify it.

 

[BradtheRad]

Enlightening answers so far.

Another reason. AM radio is susceptible to interference. Switch mode power supplies are known to broadcast stray RF (more so if it's of low-end manufacture).

Therefore the good old linear transformer-diodes-capacitor supply is a natural.

 

[ALERTLINKS]

AC is used to supply timing pulses to clock frequency for radios with clock called radio clocks. It is obsolete now i see crystal controlled timing circuits.
I have seen cordless phones, demanding ac supply. Some worked with dc also. For others,removed bridge and filter capacitor from ac adapter. AC adapter is not common.

 

[eedac]

'BradtheRad' and 'ALERTLINKS',
I heard AM radio is susceptable to noise, I thought off-the shelf SMPS is good enough to work well with it .
Now I believe that I got wrong as I saw ALL radio clock I saw is powered by battery!!!
So, linear transformers are still has market value?! ;P

 

[ALERTLINKS]

There is another type of adapter which is more common which transfoms 240v to 110v or 110v to 240v. There are also some which change frequeny ie from 50Hz to 60Hz or 60Hz to 50 Hz. But adapter concerning am radio can only be the swithing supply (which create lot of noise) and other using simple mains transformer.
Switching supply is lightweigt and more popular. AM is not heard anymore because dimmers and otherelectrical machines make noises in house in AM band. Populrity of FM radio and settilite channels is also a factor for AM radio becomming obsolete. I have not seen a single person listening am broadcast for last few years. Salesman only need to describe some good points to sell his product.

 

[Raza]

Hi eedac,
your original question:

I just heard this form a salesman and says it is popular in AM receiver....

It seems NOT kinds of SMPS. It looks like linear type adapter: i/p 230VAC to o/p9VAC(500mA).

This type of adapter has got no connection with AM radio specially. See attached images. This is my DSL modem and it's label says 18V AC and the adapter image shows out 18V AC. Though my modem works very nice with a Switching supply also but the Switching supply will definite cost more than this simple Transformer (AV/AC adapter). I have a multi band radio with Switching supply built in and is an expensive one. The guy told you that this works with AM radio was wrong.

 

[vimalkhanna]

I think there is a misunderstanding of the word AC/AC adaptor .
Actually , the Power AC recd (powerline)is having amplitude and frequency drifts as well as powerfactor deviations depending on the on the distance of the load as well as tappings enroute .There could be glitches and voltage brownouts too.
This creates problems in some zero crossing detection eqpts as well as voltage window limits.
The AC power is rectified and DC converted is used for drive of 50HZ pure sine inverter with crystal control.
This power output is used for sensitive eqpt like timer clocks ,FM switching timed radios .as well as synchros .eqpt .

 

[ALERTLINKS]

just heard this form a salesman and says it is popular in AM receiver....

It seems NOT kinds of SMPS. It looks like linear type adapter: i/p 230VAC to o/p9VAC(500mA).

This power output is used for sensitive eqpt like timer clocks ,FM switching timed radios .as well as synchros .eqpt .

Neither popular nor resemble ordinary adapter. Its only a issue of salesmen. They can sell a refrigerator to a person living in north pole.

 

[eedac]

Its only a issue of salesmen. They can sell a refrigerator to a person living in north pole.

Haha....funny! XDD...

---------- Post added at 14:18 ---------- Previous post was at 14:13 ----------

Raza, that is what they are doing. Using a AC-AC transformer accompany with some device, namely, those devices MUST have a diode bridge inside.

 

[atripathi]

AC -AC adopter mean a device which takes AC inputs and deliver AC output may be of same frequency or different frequency and voltage. Technically one can say voltage stabilizer used in household is also a type of AC adopter.

It is lot easier and cheaper to implement DC-DC controller on PCB and it will make it very small, thus several manufacturer take the transformer out of PCB or system and keep only DC-DC controller on PCB. for this case also it looks It looks like same.