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Maxwell experiments: (maxwell_notes#3)

[background]

1) Non-functioning Geiger counter from two circuits:

http://hometown.aol.com/redmo/geiger.html

and:

http://www.techlib.com/science/geiger.html

[foreground]

2) Radar/microwave detector:

http://www.electronics-lab.com/projects/misc/004/index.html

3) Wideband/broadband receiver:

http://www.techlib.com/electronics/allband.htm

Printing for PCB machen - foto resist using the Gimp: (2007.04.23:2 pcb#5 tech_notes2#3)

1) Import the PDF into the Gimp (open and set resolution to 600). Manipulate and copy as required as a layer.

2) Print settings: Set Image to line and output to Black and White

Etching PCBs using photo-resist method: (2007.04.23:1 pcb#4 tech_notes2#1)

Light documentation from workshop 21.04.07: workshops

1) UV apparatus constructed using gutted scanner with three 8W UV lights/lampe (Ersatz-UV-Roehren) from reichelt.de, three starters (from junked fluorescent tubes) and three 8W transformers from ebay.de.

useful link (see also below):

http://www.blafusel.de/misc/platine.html

2) Design laser photocopied from software-created original in this case onto diffuse transparent paper (milky). Completely transparent OHP material to be tested: (Avery Folie 3562 Reichelt again)

3) Design is placed with ink in contact with photo-sensitive (fotopositiv) PCB material from Conrad. Plastic protection is first peeled off - all of this process in near darkness. PCB is exposed for three minutes to UV light using a darkroom timer to time this.

4) Pre-mixed developer/entwickler (Natriumhydroxid from Conrad - 10g to 1 litre of 20 degree C water. Development time varies from three to five minutes as developer ages.

5) After development rinse in cold water and develop in etch solution (see: simple_pcb_guide for this part of the process.

6) Scrub off the yellow photo-resist with water and a brillo-pad and clean a bit with alcohol. The results: