Page 1 of 1

Extension board 5V

PostPosted: Wed Nov 14, 2012 5:28 pm
by Rico21
Hi Tom,

Before assembling the gluonpilot module with the extension board I've verified the tensions on extension board.
I've found 5V equal to 5,463, it's a little bit far from 5.25V (5%). After reading the datasheet of the PTH08080, it seems the resistor Rset (R3 on extension board) must be at 348 ohms to get exactly 5V. However R3 indicates 121, this mean 120 ohms. For 117 ohms the datasheet gives a tension of 5.5V. So it seems to confirm that R3 resistor is not at the good value.
What do you think of this?

Thank you Tom

Regards

Eric

Re: Extension board 5V

PostPosted: Wed Nov 14, 2012 5:39 pm
by Tom
Hi Eric,

You have a good eye ;-)

Yes I was a bit puzzled when designing this. There is no component requiring exactly 5V. Because of the diode (http://www.digikey.be/search/en/1N5819H ... mId=981138) which has voltage drop of 0.45V under load, I decided to use 120 Ohm for ~5.5V. So 5.5V - 0.45V = 5.05V. When measuring without any load, you will indeed have a lower voltage drop and the voltage will be above 5V.

Re: Extension board 5V

PostPosted: Wed Nov 14, 2012 5:53 pm
by Rico21
Thank you Tom for you quick answer, so no problem to connect the module gluonpilot and the extension board!
Let's try :D

Regards

Eric