LCD+2 power connections

Started by Brian Little October 1, 2005
I have had a bad experience with using a Radio Shack power adapter
(1.5V - 12 V 300mA) with the LCD+2 using the onboard female plug to
the adapter. It burned out the board due to it supposedly putting
out higher voltage than the 12V I had it set for. I purchased a
replacement LCD+2. I am somewhat cautious about connecting power to
the LCD+2. So I have three options in mind and want to get advice on
if these are safe options.

Option 1: Connect a 9V battery to a male plug (center pole positive)
and use the female plug on the board of the LCD+2.

Option 2: Connect the + and Gnd pins of the Development Station
(near the BX-24 socket) and connect it to +5 and Gnd pins of the Aux
Port on the LCD+2.

Option 3: A 5 volt regulated output powered by a 9V battery and
connect it to +5 and Gnd pins of the Aux Port on the LCD+2.

Thanks in advance for any advice.

Remember, those cheap supplies are rated for the specified voltage
at the specified current. At less power draw, the voltage will be
higher, potentially much higher depending on the internal resistance
of the transformer.

My 12V 1A wall wart puts out about 18v with no load.

You COULD set the variable voltage to much less than what you want
and then ramp up the voltage until good things happen.

Better yet, get a more regulated supply! Batteries are OK, but 9v
bateries have very little juice.

Better to get a stack of rechargables, like 9.6v (8 cells). This
would be a good way to source 9.6v. 6 cells would get you 8.4
volts, and might not allow much power to be drawn before it drops
below the minimum voltage of the LCD2+ voltage regulator (likely to
be around 7 volts).