On 22 Mar 2005 11:02:07 -0800, "Tim Shoppa"
wrote:

Neither schematic shows the most expensive components: the transformer
and filter caps.

If you have a 24VAC transformer and a full-wave rectifier you have
something like 31 or 32VDC under full load. That's not a lot of
headroom if you have brownouts etc to worry about.

It also seems that neither has any overcurrent/crowbar protection. If
your pass transistor fails shorted and everything still works and
nothing blows up... maybe you didn't need a regulator in the first
place :-).

Tim.

In nearly 40 years years I have dealt with semiconductors I have never
experienced that crowbar has been a need for the power supplies used
on this side, but what I can say about many constructions seen, I
would use them without crowbar because they are sensible to RF, and
often not well designed in other ways
I usually have current protection, but for simplicity it isn't shown
here, I also considered to use a simple thing as an old fuse since
shortcircuiting the output hasn't really occured more than a few times
here.

I intend to use toroid transformer, and believe the output voltage
varies somewhat more than for a standard E-core transformer

73
jan-martin, LA8AK
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/91n.htm