If the base is being driven by a 13.6V zener and the collector has 26V, then
I'd expect a 13V output on the emitter.

---.--------.---------------------. -26V
| | |
| x |
| x 5k6 |
| x |
| | |/
= 100uF .-----.--xxxx--------|
| | | 470R |\
| V | |----- -13V
| ~ ZD = 10uF = 10uF
| | | |
---.--------.-----.----------------.----- 0V

If the above is about right then any PNP with a suitable rating should do,
and no you probably can't use the VR you have as -15V will probably be too
high for the following circuits.

Dave

"Dave" wrote in message
news:EYVTf.6018$J43.3427@edtnps90...
"David C. Partridge" wrote in message
...
I'd think that any PNP power xistor with an adequate voltage rating would
do - this is just a pass xistor wired as an EF isn't it?

David

I know very little of transistors other than their basic function, so I
don't know the answer to your question above.

As I noted, it's being used to (down)-regulate negative DC voltage. What
might the reason have been to opt for this transistor over a regulator?
There is a +5VDC regulator right next door in the same circuit.

Can I use the regulator in place of the transistor?