Difference between online and offline P/S? (2)

Thread Starter

arif haq

Joined Mar 18, 2024
1
In electronic circuit why technically saying for example uc3843 is off line ic what that mean? Where as it uses main voltage i never understand this phenomena !

Moderator edit: New thread created from this.
 

Papabravo

Joined Feb 24, 2006
21,324
In electronic circuit why technically saying for example uc3843 is off line ic what that mean? Where as it uses main voltage i never understand this phenomena !
Refer back to post #2, in the original thread.

An online supply operates directly from the AC mains without a mains transformer which operates at the powerline frequency. The mains are directly rectified to a high DC voltage and then run through a DC-DC conversion process at a much higher switching frequency than the frequency of the mains.

An offline supply operates from a DC source supplied by a battery or by a DC power supply with a mains transformer, rectifier, and filter.

One type has a mains transformer in the conversion path and the other does not. Simple as that.
 
Last edited:

MisterBill2

Joined Jan 23, 2018
19,474
OK, that is a reasonable distinction, but at one time I had thought it applied primarily to standby power systems, where "On-Line" meant that in the event of a mains loss there was not even any disturbance in the output, while "OFF-LINE meant that when the mains failed the backup supply would start up and take over, within some short time period, up to a few minutes.
So the on-line system had the mains power feeding a battery that directly fed an inverter supplying AC power to some critical load. THAT was one definition back in 1968. Those definitions are also reasonable, but not the same.
 
Top