PAGES

Monday, January 3, 2011

Power Testing

01-03-2011, 01:55 PM 5-97 POWER TESTING

    * Modified Parallax Propeller Proto board (both regulators and LED disabled) draws 4mA idle. Power LED converted to data light draws 20mA when on. Another test confirmed 4mA modified board current. Unmodified, board draws 10mA. To modify, lift the middle leg of the 3.3 vdc (output leg) of the LM1086 CS-3.3 regulator.

    * Another test, mod proto board draws 5ma, 19ma with on board data light. Put Taiwan LED on pin 25 with 150 ohm resistor = 12ma. Draws 6ma with 2.2k ohm. (since board draws 5ma, the Taiwan LED is drawing only 1ma)

    * Power LED converted to data light still has a 241 ohm resistor on it which is too small a value and that is why you see 20ma current. This is not acceptable for the purpose of battery portable operations. Therefore another data LED will be added.

    * The China red LED is the same as the red Taiwan LED – very bright at only 1ma. The green China LED is barely visible. (using a 2.2K ohm resistor). The green Taiwan is also too dim. The yellow Taiwan LED is also the same/ too dim.

    * The secondary LED was tested with a 2.2K resistor and was bright. With a 4.7K, it was less bright but still usable. You would not want to go dimmer. Therefore, with the Prop's 3.3 volt pin, use a resistor from 2.2K to 4.7K range depending on desired brightness. Both tests showed the LED drawing 1ma.