fyp_week 8 and 9 : Pcb etching circuit electronic stethoscope

STEP PCB ETCHING

1) 

we design the circuit electronic stethoscope on express-PCB board

2)

express-PCB board

 

printer laser jet

 

 transparent paper

we print circuits Electronic stethoscope that have been made on express-PCB board by using transparent paper and used the printer laser jet.

3)

buy the PCB UV board. We cut PCB UV board to size demanded in circuit.

4)

after cut the PCB UV board.we go to Lab etching and make the PCB UV board on the UV box. way used the UV box is set time at the UV box. we choose 60 second. result PCB UV you can see the gold line in PCB UV.

5)

after used UV box. to remove the gold line is at PCB UV board. used the etched with a 220 g/l solution of ammonium peroxydisulfate (NH₄)₂S₂O₈ a.k.a. ammonium persulfate, 220 gram added to 1 liter of water and mix it until everything is dissolved. Theoretically it should be possible to etch slightly more than 60 grams of copper with 1 liter etching solution.Etching at ambient temperature might take over an hour, it is better to heat up the etching solvent to about 35-45 degrees Celcius. After an etching procedure it gradually becomes blue and more deeper blue - the chemical reaction creates dissolved copper sulfate CuSO₄. Compared to other etching chemicals like hydrated iron (III) chloride FeCl₃.6H₂O a.k.a. ferric chloride or the combination of hydrochloric acid HCL and hydrogen peroxide H₂O₂, using ammonium peroxydisulfate is a clean and safe method.

6)

lastly we get the circuit in etching PCB