Video Isolation Transformer

Oct 30, 2013 7 Replies

I've just repaired a transformer based video isolation unit. This paticular unit has centre tapped primary and secondary windings with a series RC network between the two taps (see the sketch at

formatting link
).



I can't quite see why these components have been added - any ideas?


** Instead of wasting our time by making us guess about all the details YOU LEFT OUT - how about you remove the RC network and see what changes.

Hint - it may well be a frequency response thing ....

.... Phil

The only explanation I can think of is to reduce HF common mode capacitive feed-through. The effectiveness would be dependent on the relative locations of the 4 windings.

Mike Perkins Video Solutions Ltd www.videosolutions.ltd.uk

This broad spectrum transformer gives 1:1 differential gain with excellent low frequency common-mode rejection that might be a concern from ground hum. The RC coupler provides a low common-mode impedance good for rejecting stray capacitive noise.

That --||-- thing may be a tiny metal oxide varistor.

Most isolating transformers at the edge of an appliance have something to prevent static electricity buildup.

"Kevin McMurtrie"

** And if the GoogleGroping OP had provided even the most basic details WE would not be in any doubt about such matters.

All fools like him want is to make people guess - then pick the guess they prefer.

Purest bollocks.

.... Phil

Don't you ever tire of the role of village idiot?

"Kevin McMurtrie"

** And if the Google Groping f****it OP had provided even the most basic details WE would not be in any doubt about such matters.

All fools like him want is to make people guess - then pick the guess they prefer.

Purest bollocks.

.... Phil

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required