[0-30 Vdc Stabilized Power Supply]

I've been reading thru all the posts (phew) to try and learn a few things. I've also tried to calculate the values of the resistor and zener using the info here:

http://www.satcure-focus.com/tutor/page5.htm

I measured the rectified (4 x MBR1060) output filtered with 4700uF loaded with R1 (2k2), giving 54.7VDC. Loading it with a 200R resistor gives 44.5VDC.

Choosing a zener arbitrarily (BZX79C43, Iz=2mA) I end up choosing a 100R resistor, giving 5W for the zener so I need a higher rated zener. However this raises the needed current for the zener, and thereby again the current in the zener. Is this right?

Since high wattage zeners are not readily available, could I do something like this?

http://sound.westhost.com/appnotes/an007.htm


Another approach:

The OPA445 is within it's voltage raiting, but how about the rest of the circuit? On that note, I've seen the OPA551 mentioned. Could this be used (it's cheaper than OPA445)?

And another question:
What's the purpose of R1?


Thanks for helping out :)

[0-30 Vdc Stabilized Power Supply]

I've attached a schematic, is this what you were thinking?

I'm really not on top of the theory behind this circuit, but I've tried to sim it, and play around with the values. The cap after the darlington I believe is there to stabilize. Any idea how low you can go on this value?

Thanks!
soje

cap_mult.pdf

[0-30 Vdc Stabilized Power Supply]

Another thought (dangerous, I know :-))

Could I use a capacitance multiplier right after the rectifiers somewhat like this:

http://sound.westhost.com/project15.htm

and adjust the 12k resistor to lower the voltage into the psu circuit?


Regards
soje

[0-30 Vdc Stabilized Power Supply]

That's what I was afraid of. Darn :-)

Thanks for your reply.

Regards
soje

[0-30 Vdc Stabilized Power Supply]

Hi.

I'm gathering parts for this project, and I have a 2x15VAC 4A trafo at hand. Unloaded it delivers 34,4 VAC with the two sides in series. Will this be too much for the circuit?

I've seen 30vac mentioned for the trafo, so I hope this isn't a stupid question  :-[


Regards
soje