Re: Transistors

On Mon, 19 Nov 2007 01:06:57 +0100, Fred Bartoli <" "> wrote:

Jim Thompson a écrit :
[snip]

Solved an IC problem once by adding an extra layer of metal that
covered all junctions.


On my 200pV/rtHz preamp I first had a huge unexpected 1/f noise with
very unstable level.
Scratched my head for almost one day long. Then the problem suddenly
disappeared when clouds came masking the sun.
Gasp! The path was through the window, reflecting on the lab walls, then
reflecting up on the PCB and finally entering the IF3602 jfets through
the glass beads sealing can.

Don't "mystery failures" really drive you nuts?

Had a problem with a JFET OpAmp breadboard just up and literally
smoking. Took me a week of failures before I determined that the Moto
RF guys had moved into the lab next door... every time they keyed
their transmitter my OpAmp breadboard went bye-bye :-(

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

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