The transformer centre tap must be connected to the Zero Volt Rail.
I consider the best place for that connection to be right above the C10 label, between the first two capacitors.
This same connection must also be taken to the chassis.
The chassis must have a permanent Safety Earth that connects to third wire in the mains supply cable (PE).
This PE must go back to the distribution board without any breaks.
I consider the best place for that connection to be right above the C10 label, between the first two capacitors.
This same connection must also be taken to the chassis.
The chassis must have a permanent Safety Earth that connects to third wire in the mains supply cable (PE).
This PE must go back to the distribution board without any breaks.
ok now I try this fixing with PCB hope this one is correct and for Earth grounding I use same cable from the transformer that ground 0 I suppose its ok but if not what I should do to keep it more safer as this board seems extremely charged and danger even with fuses.
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Hosam,
Asalam Aleikum, Marhabba,
The picture you attached is not so clear.
A proper schematic is attached below.
Pleas note that if you need +/- 45Volt, the transformer should be around 90Volt center tapped, because of each rail (the positive rail and the negative rail) will get 1/2 of the voltage between the (+) and (-) terminals of the bridge rectifier.
Asalam Aleikum, Marhabba,
The picture you attached is not so clear.
A proper schematic is attached below.
Pleas note that if you need +/- 45Volt, the transformer should be around 90Volt center tapped, because of each rail (the positive rail and the negative rail) will get 1/2 of the voltage between the (+) and (-) terminals of the bridge rectifier.
Attachments
I stand corrected. The transformer's secondary should be around 57Volt AC, center tapped. That is, a secondary of 0-28.5-57Volt AC. 45Volt AC secondary will get +/- rails of about 35Volt DC.
An externally hosted image should be here but it was not working when we last tested it.
It's really straightforward.
after build this power supply now things get complicated because I get 55v DC from it and I'm afraid that I could fire the TDA7294 cause it could handle without load only max 50v so any suggestion to down the extra 5v or it could work with it?
In the case of TDA7294, which draws so little current in quiescent mode (no signal) and so much current under full output power, the only option I see is to change the power transformer.
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