The setup: Just the Uno and LCD connected so:
LiquidCrystal lcd(7, 8, 9, 10, 11, 12, 13);
- Simple sketch to send and receive characters by monitor.
- Powered By Laptop USB
- LCD Back Light 8.5 mA. @ 5.04 v.
Experiencing some flicker on LCD and Pin 13 led.
Powered By 12v battery to DE-SWADJ - 10W 1 Amp Step down adjustable switching regulator @ 9 v.
- Battery @ 12.7 v.
With no load, regulator is using 19.1 mA.
Connected battery to Uno at Vin pin and also tried using the plug w/ 9 v.
On battery only, w/ Uno and 2 Line X 16 Character LCD Display with Blue LED Backlight
- 12.7 v. @ 65.2 mA. For 828 mW.
- 9 v. Regulator @ 54.1 mA. For 487 mW.
- 487 / 828 = 0.5882 59% efficiency
On Battery and Laptop USB
- 12.7 v. @ ~ 40 mA.
- 9 v. Reg. @ 32.6 mA For 293 mW.
- So USB is providing ~ 487 - 293 = 194 mW.
I was under the impression that when Uno is on external power that it would not use laptop or USB power.
Question: Am I wrong? Or Is my Uno board partially damaged?