+/-15vdc 7815, 7915 Power supply

[argonrepublic]

Could someone please send me a link to schematics? I recently put together a supply with LM317, LM337 for +/- 15VDC but I want to make similar but fixed supply with 7815 and 7915. I only require about 1 ampere. My transformer is not center tapped. It has been working ok with my adustablle regulators.
Thanks

 

[gmphadte]

ti.com

Just search for fixed voltage regulator or 7*15 and download the datasheet. You will have to provide input dc voltage within the specified range.

Gajanan Phadte

 

[kroto]

Voltage Doubler

without center tapped trafo you will need to use voltage doubler configuration.

schematic attached.

 

[argonrepublic]

My transformer is 38 VAC

 

[spwalek]

check this out on Rod Elliots site I think this will work with your transformer.

Power Supply for Preamps

 

[theAnonymous1]

Like kroto suggested, you need to make a voltage doubler.

I built the one from the above link some years ago...

 

[Sorento]

38vac is too high for voltage doubler, thats over 50vdc per rail on idle
7815 don't like more than 35v input
QUAD used a capacitive splitter w/o doubler in their 606 amp to obtain virtual gnd
http://www.keith-snook.info/Schematics/QUAD 606 Schematic circuit.pdf
note T15 / T16 device to keep balance

 

[gootee]

There is no limit on input voltage. The limit only applies to the difference between the input and output voltages.

 

[Sorento]

There is no limit on input voltage. The limit only applies to the difference between the input and output voltages.

true for the adjustable variety like LM317
but not so for the fixed voltage type ...
the O.P. wants to use 7815 though and these unfortunately do have input voltage limits

 

[myhrrhleine]

You should be able to use 1/2 wave rectifiers for this rather than a bridge,
thus having two voltages referenced to ground.

At any rate, 38 volts is more than enough for even a full wave bridge, no need for a doubler.

 

[gootee]

true for the adjustable variety like LM317
but not so for the fixed voltage type ...
the O.P. wants to use 7815 though and these unfortunately do have input voltage limits

Oops. Sorry.