Electronics Forum / Basics / April 2007

Well, I had high hopes for the bypass cap on pin 7, but unfortunately
it didn't help. I tried various caps (0.4uF, 1uF,22uF) from pin 7 to
ground with no improvement. Also tried small caps across the chip
power pins with no change.

-Bill

Projection.

I've never needed to nor do I wish to. It's rubbish and I have no use for it. My
preference going back to days of old was TI's SN76023. You could make one of
those perform surprisingly well !

I'm sure it would present no problems to an expert in audio amplifiers like
myself though. After all, my 2kW amplifiers work beautifully and have
class-leading performance figures and need I add, totally unconditional
stability.

Graham

 I have a few mica smt caps that work very nicely, they are expensive
how ever because they are hard to make..
  When I was working at Semco as an consultant, I was part of a project
where we automated a robotics arm that had visual to the computer.

  The arm used a mini vacuums finger to pick up the mica sheets to be
stacked.
   This process would pick a cut piece from a pile, visually inspect it
for defeats first, put it under a pressure plate where High voltage was
applied for leakage test. If all of that passed, it was then pick up
and place in a contact frame where the cap was being assembled.
  Very thin silver foil was laid between for the plate's from a  mini
spool entering from the side's of the frame..

 When the stack was complete, a push finger comes down along with a
button lift finger that pushes it out of the contact frame and is
compressed between these 2 fingers as it is quickly hit with a HOT
iron (very small) to bond the foils..
 from there another HV test is done along with capacitance test which
will very the compression tension of the fingers to make adjustments on
the fly.
 the next process then passes this over to two other holding fingers
where the encapsoluation is applied and harden with UV (Very Strong) UV.
 then another test is done, then they are place in little strip frames
for later encaps and printing ..

  All of that above it done using robotics arm with attached video camera's
into a PC using DELPHI has the graphics and guidance for the movements.
  Things were color coded on the table to make it easy to track.
 this may sound like a lot of steps how ever, the process actually was
very fast once you got it going. the operators only needed to dump small
piles of pre-cut mica on a pick up area. From there, the robotics did the
rest.
  Before that time, the Japanese was the only one's making then and
their yield was like 5 out of 10 good, and that was done by hand as for
as the stacking.
 We also suffered the same problem, but after the automation, it was
like 99.99% good other than an unexpected machine failure/Jam up.