Hi, I'm finishing my homemade arduino, but when I was going to put the c9 capacitor I've got a problem.
In the schematic it seems to be a polarized electrolytic capacitor, but in the mounting diagram not.
What should I do?
Thanks for your time!
Flakifero.
Both images are from the Arduino Single-Sided Serial Board Manual that is posted in http://arduino.cc/en/Main/ArduinoBoardSerialSingleSided3.
Don't know what to do, I don't want to mess the project with that :s.
This section of the Arduino is a voltage level converter to convert from +12v to -12v RS-232 serial to TTL 5 volt serial. The capacitor in that position will see positive and negative voltage (RS-232 Computer TX Data). This is borne out in the spec for that component which specifies a 10uF NON-POLARIZED capacitor. The entry in the component list is as follows:
1 C9 non-polarized electrolytic 10[ch956]F (10 micro Farad) 16volts (or more: 25v, 50v) radial-lead capacitor
You will need to get a non-polarized electrolytic for component C9.
Thank you very much! tomorrow I'm going to buy a NP capacitor and do it. Now I understand how does it works.
Flakifero
Glad to be of help!
When I started tracing that circuit out, I thought, "Hey, wait a minute, that thing's effectively got AC on it! And no bias voltage to keep it from reverse polarity." Sure enough when I checked the parts list...
The plus symbol on the placement mask is probably an artifact left over from the Eagle part definition, they realized that and changed the schematic to properly reflect non-polarized, but the mask didn't get updated.
flakifero,
read this:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1232661462
If you cannot find a non polarized cap, you can use a polarized one, with plus (+) terminal to the ground.
And here the discussion about the development of the new board version (from v2 to v3-Severino).
C8 was C9 at that time.
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1177923417/4