Difference between revisions of "N2PK VNA"
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* [http://n2pk.com/VNA/VNA-below3-1.jpg PCB bottom side] | * [http://n2pk.com/VNA/VNA-below3-1.jpg PCB bottom side] | ||
== Notes == | == Notes == | ||
| − | + | * [http://www.benl.ebay.be/itm/290807419665?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 The caps I bought] | |
== Components == | == Components == | ||
Revision as of 02:48, 16 October 2013
Contents
Documentation
Notes
Components
Missing
Bottom side
- R160a - R166a: I used 270k instead of 220k
- C115-117,126,127: 10uF 16V X5R 1210
- C180-C184
- C170-C174
- R250: 3.3R 5% 0805 - I have 1.8R, 3.9R
- C250, 280,281,292: 10uF 16V Tant 20%
- C213, C290 100nF X7R
- C280,281,292
Top side
- C251 100nF X7R
- Q190,270: npn tx
- C125: 1uF 25V X7R 10%
Questions
- All caps seem to be NPO, X7R, X5R, or Tant. NPO = temperature independant, X7R & X5R = ceramic, Tant = tantalum. Problem: I only have an assortment, no other specs (prob. ceramic?)...
- R160a - R166a should be 221K. They are part of (what I assume to be) an RC filter, and a load for that filter (the input impedance of that buffer IC is probably quite high). These are digital lines. I don't have those values, so I was thinking about taking 1k2/75pF for the RC filter, and 270k for the load. I don't see why it should be very critical.
