Shouldn't a 6v powersupply work for the arduino?

Hey!

I have a 6vDC 150mA power AC adapter that I plugged into my arduino uno put it is not turning on. The spec sheet said it should operate anywhere in the range of 6-20V. The current should be irrelevant so what is the problem?

McK

Could it be that the polarity of your AC adapter is wrong? I think the Arduino requires + to be the center electrode. There is a protection diode that will block reverse-wired power.

Current is not entirely irrelevant. The Arduino does draw some power. Have you tried measuring the voltage coming out of your AC adapter under load? Connect your meter - to Ground and + to Vin.

The spec sheet said it should operate anywhere in the range of 6-20V.

No it says 7.5V, 6V is too low for the regulator on the arduino board. The protection diode drops 0.7V anyway so you are only presenting the regulator with 5.3V which is way too low for it to regulate.

Plus the other stuff that johnwasser said.

Grumpy_Mike:

The spec sheet said it should operate anywhere in the range of 6-20V.

No it says 7.5V, 6V is too low for the regulator on the arduino board. The protection diode drops 0.7V anyway so you are only presenting the regulator with 5.3V which is way too low for it to regulate.

Spec sheets for the Arduino UNO R2, UNO R3, UNO SMD, Duemilanove, Diecimila, Mega, and Mega 2560 say:

Input Voltage (recommended): 7-12V Input Voltage (limits): 6-20V

Maybe they are using an LDO regulator or maybe, since the ATmega can easily run at 4.5V, they don't mind if the regulator output is a little below 5V.

You can check them here: http://www.arduino.cc/en/Main/arduinoBoardUno http://arduino.cc/en/Main/ArduinoBoardDiecimila http://arduino.cc/en/Main/ArduinoBoardDuemilanove http://arduino.cc/en/Main/ArduinoBoardMega http://arduino.cc/en/Main/ArduinoBoardMega2560

Spec sheets for the Arduino UNO R2, UNO R3, UNO SMD, Duemilanove, Diecimila, Mega, and Mega 2560 say:

Input Voltage (recommended): 7-12V Input Voltage (limits): 6-20V

It might say that but it is wrong. There is so much "official" stuff that is wrong. Simply 6V is too low to drive an arduino. You might get something in the order of 3.5V out but that is too low to reliably drive a 16MHz crystal.