🚀 go-pugleaf

Watson wrote...
>
> I can get the TL431s or TL430s, but I've never seen the LM385-1.2,

 http://www.national.com/ds/LM/LM185-1.2.pdf

 The LM385 is the classic bandgap reference IC, made by National
 Semiconductor, TI and LTC.  Digikey has 5757 of NSC's TO-92 at $0.77,
 http://www.digikey.com/scripts/us/dksus.dll?Detail?Ref=15244&Row=218216

 NSC has free samples, http://www.national.com/pf/LM/LM385-1.2.html

 Recommended.  Also check out the LM385-2.5 and the LM385-adj parts.

> probably the closest I could come is the following.  Maybe you'd
> like to comment on this one.  It sems to give constant voltage, but
> it apparently doesn't have temp compensation.  I guess it works
> similar to your upper circuit, but wih two transistors?  
>
>         --+-----  Unreg V          
>           |
>           \
>           / To give a few mA, maybe 1k
>           \
>           /
>           |
>           +-------->  Constant V, about 1.4V
>           |           
>            \E |
>    PNP       \|
>    2N         |-------+
>    3906      /|       |
>            /  |       |
>           |           |
>           |           |
>           |           |
>           +--/\/\/\---+  Less than 10 ohms
>           |           |
>           |           |
>           |       |  /
>           |       |/     NPN
>           +-------|      2N
>                   |\     3904
>                   | E\
>                       |
>                       |
>                      ===
>                      GND

 I see you're having fun with your explorations, and that's good. 
 Yes, the results will be similar to a Vbe reference, as least as
 far as tempco and dynamic resistance are concerned, but it does
 lack voltage adjustability and an easy way to null the dynamic
 resistance.  :>)
 

 Thanks,
    - Win