[sci.electronics] looking for part

earl@phred.UUCP (choo choo earl) (11/15/90)

Hi there.
I'm looking for information on a part I used to use but has since gone out
of existance.  The part was numbered LP1000 and was made by Lithic Systems
back in the mid 1970's.  It was listed as a mizer circuit, and was used for 
oscillator and flasher circuits.  The part was housed in a TO-92 can, with 
three leads.  The data book had the "equivilent circuit" listed, and we
constructed some from this that worked. If anyone has information on a 
replacement part, or has a copy of the old data book, I would sure like
to find out. 
The circuit worked using a negative resistance principle.  A capacitor
was charged through a resistor, and when it reached the trigger voltage,
the IC would discharge it through the load.  I know there are other IC's
that do this, but this one worked just off the capacitor voltage, and didn't
draw any quiescent (sp?) current.  The basic operation was like a neon
lamp oscillator, but this all happened at 4V.  
Thanks in advance.
earl@phred
Physio-Control Corp
(206) 867-4255
 
-- 
DIG A DUCK DIG A DUCK DIG A GEODUCK DIG A DUCK DIG A GEODUCK DIG A DUCK A DAY
These opinions are mine.  Nobody else wants them.
earl@phred      Physio Control Corp.   Redmond Wa   (206)867-4255
so there

spcecdt@deeptht.santa-cruz.ca.us (John DuBois) (11/20/90)

In article <3288@phred.UUCP> earl@phred.UUCP (choo choo earl) writes:
...
+The circuit worked using a negative resistance principle.  A capacitor
+was charged through a resistor, and when it reached the trigger voltage,
+the IC would discharge it through the load.  I know there are other IC's
+that do this, but this one worked just off the capacitor voltage, and didn't
+draw any quiescent (sp?) current.  The basic operation was like a neon
+lamp oscillator, but this all happened at 4V.  

     Try a PUJT (Programmable Unijunction Transistor).  It will do what
you want, and can be programmed to trigger at any voltage in its range.
It draws essentially no current in itself; the only current that flows is
the capacitor charging current.  Also, input impedance is extremely high
(except when it's triggerred!) so you can get very long delays (several
hours) with miniscule currents.  A "drip" circuit based on this is
pretty nasty  :-)  Anyway, PUJTs are cheap and plentiful.
     I've never heard of a "mizer"; perhaps it was actually a UJT
(unijunction transistor, a nonprogrammable device)?

-- 
John DuBois
spcecdt@deeptht.santa-cruz.ca.us