variable B+ supply

[kambo]

any schematic appreciated

 

[emrr]

What voltage range and current?  If you want an old classic, look at the Heathkit IP-17.

http://www.mcmlv.org/Archive/TestEquipment/IP17.pdf

dig around in here:

http://www.one-electron.com/FC_TestEquipment.html

 

[kambo]

thank you Doug,

i am looking for 250-320 V range,

 

[volker]

http://www.roehrenkramladen.de/hboexp4/hboexp4.htm

The voltage is adjustable from 0,7V to 330V via R7, the current can be limited in the range of 30-170mA via R6.
If you need any further information I can translate for you.

 

[kambo]

thats excellent, thanks Volker,

 

[EZ81]

This one might offer better regulation if you can live with 5 mA quiescent current: http://www.national.com/ms/LB/LB-47.pdf . In 2010 one would rather use a MOSFET a la IRF820 instead of the Darlington pair.

 

[kambo]

thank you, i am checking tl783 data_sheet too...

 

[CJ]

the fairchild 670 pwr supply has a range like you need,

 

[kambo]

thanks CJ, never noticed this is some PSU and a half
what is the purpose of switch (?) above the screw mark... connected to V303 - R313 150k

 

[PRR]

R313 is an internal trimmer to set the output voltage.

The cross-arrow (pointing down) shows which way to turn to increase output voltage.

I believe the dot and ground is a transcription error.

 

[kambo]

thank you