Dual outputs from one transformer secondary ?? - UK Vintage Radio Repair and Restoration Discussion Forum

milairuk · 11th Feb 2007, 3:50 pm

I want to have two switched HT outputs, both individually selectable high/low, but want to use only one transformer. Given that the current rating would be split between the two rails, would the attached circuit work or am I missing something? Voltages given are just notional at this time.
Ideas / comments invited

oldeurope · 11th Feb 2007, 4:39 pm

Quote:

Originally Posted by milairuk

I want to have two switched HT outputs, both individually selectable high/low, but want to use only one transformer. Given that the current rating would be split between the two rails, would the attached circuit work or am I missing something? Voltages given are just notional at this time.
Ideas / comments invited

Hi,
if one output is switched high, the other one will be high too

!?!

Kind regards,
Darius

milairuk · 11th Feb 2007, 4:42 pm

Quote:

Originally Posted by oldeurope

Hi,
if one output is switched high, the other one will be high too

!?!

Kind regards,
Darius

Sorry I may not have decsribed this well - The switches are not ganged, SW1 & SW2 are seperately selected, so HT1 can be set to 350v, whilst HT2 can be set for 250v, Or the opposite, or both at 350v or both at 250v.

oldeurope · 11th Feb 2007, 5:00 pm

Quote:

Originally Posted by milairuk

Sorry I may not have decsribed this well - The switches are not ganged, SW1 & SW2 are seperately selected, so HT1 can be set to 350v, whilst HT2 can be set for 250v, Or the opposite, or both at 350v or both at 250v.

Hi,
you described this well. If SW1 is switched to 350V and SW2 is switched to 250V both will be 350V. I am sure (at the moment, hi hi).

Darius

Ed_Dinning · 11th Feb 2007, 5:34 pm

Hi , the common ground connection will give problems. You would be better using simple 1/2 wave rectification and larger caps. Then switch your "outputs" to the desired supply. Note that you may need substantial switches as it will be DC.

Ed

milairuk · 11th Feb 2007, 7:32 pm

Quote:

Originally Posted by Ed_Dinning

Hi , the common ground connection will give problems. You would be better using simple 1/2 wave rectification and larger caps.
Ed

Thanks Ed, I had a feeling that the common ground would cause a problem. Your suggestion is so damned obvious. Sometimes ideas get overcomplicated

I'm not too worried about ripple as the solid state regulators will give 60dB rejection on their own.

John

11th Feb 2007, 3:50 pm	#1
milairuk Pentode Join Date: May 2005 Location: Chelmsford, Essex, UK. Posts: 150	Dual outputs from one transformer secondary ?? I want to have two switched HT outputs, both individually selectable high/low, but want to use only one transformer. Given that the current rating would be split between the two rails, would the attached circuit work or am I missing something? Voltages given are just notional at this time. Ideas / comments invited Attached Thumbnails

11th Feb 2007, 5:34 pm	#5
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Dual outputs from one transformer secondary ?? Hi , the common ground connection will give problems. You would be better using simple 1/2 wave rectification and larger caps. Then switch your "outputs" to the desired supply. Note that you may need substantial switches as it will be DC. Ed