Author Topic: Are those switching transformers  (Read 370 times)

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Offline fixit7

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Are those switching transformers
« on: June 04, 2019, 11:10:31 pm »
 

Offline Stray Electron

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Re: Are those switching transformers
« Reply #1 on: June 04, 2019, 11:25:12 pm »
  You might bet more replies if you used a picture host that doesn't require that we join and log into.
 

Offline fixit7

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Re: Are those switching transformers
« Reply #2 on: June 05, 2019, 12:25:36 am »
 

Offline ArthurDent

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Re: Are those switching transformers
« Reply #3 on: June 05, 2019, 12:39:22 am »
Front looks like switching transformer, rear one is A.C. line common mode choke.
 
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Offline fixit7

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Re: Are those switching transformers
« Reply #4 on: June 05, 2019, 01:52:28 am »
Thanks for the help.

Andy
 

Offline strawberry

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Re: Are those switching transformers
« Reply #5 on: June 05, 2019, 06:49:32 am »
Front looks like switching transformer, rear one is A.C. line common mode choke.
It is flyback topology swithcing mode power supply. It is not exactly a transformer but gapped inductor with secundary winding. Its output voltage is not determined by turns ratio
 

Offline fixit7

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Re: Are those switching transformers
« Reply #6 on: June 05, 2019, 12:59:45 pm »
Thanks.

Quote
Switch mode power supplies

An SMPS, or switcher, is a power source that uses a switching regulator to maintain stable output voltage(s) from an AC or DC source. The switching regulator uses one or more semiconductor devices, such as a bipolar junction transistor, MOSFET or IGBT, switching between ‘On’ and ‘Off’ states to maintain output voltage regulation. These devices can operate with fixed ‘On’ time and variable frequency, or more commonly, at a fixed frequency and variable duty cycle. High efficiency results from the low power dissipation of the switching device when it is either ‘On’ or ‘Off’. The device dissipates power only during the transitions between states. Also, because the switching frequency is generally in the tens of kHz, transformers, inductors and capacitors can be much smaller, giving high volumetric efficiency.

The advantages of the SMPS are countered by the potential for electromagnetic interference (EMI). This is due to the switching transients and can be ameliorated by careful component selection, layout and shielding.

Is the shielding similar to the copper/zinc mesh  that I have seen?

I am reading Understanding Basic Electronics by Larry Wolfgang and one chapter mentioned EMI.

« Last Edit: June 05, 2019, 01:01:26 pm by fixit7 »
 

Offline strawberry

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Re: Are those switching transformers
« Reply #7 on: June 05, 2019, 03:00:25 pm »
Is the shielding similar to the copper/zinc mesh  that I have seen?
if wire is surrounded by copper mesh, it becomes shielded wire or cable.
transformers are shielded with copper tape or steel cage/box to reflect and absorb radioation, most of it
you can shield sensitive components from noise or the noise source or both
 
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