I've got a board powered from 12V, which then regulates it down to 5V. The 5V regulator is tapped for 3.3V and 2.5V supplies. The only thing that the 12V input is connected to other than the 5V source is a few opamps which are used to provide scaled analog references for these voltages. I don't mind having these references nonfunctional, but I'd rather desolder them than blow something up.
Does anyone have experience with this? I'd try it, but they're soldered to the PCB.
The first thing that happens when you apply a voltage to the input of a 741 when it's powered off is you feel great shame.
2. Nothing much will happen, but there will be current flow if V- is grounded. Even if the input fries (won't with those voltages), there isn't much place for the current to go, so it shouldn't overheat. Looks like path of least resistance may be out null offset pin if it's grounded.
Q3 Q4 essentially quench current flow without power, though.
guess if the input BE junction zeners out, they would be forward biased... but now I'm talking out of my butt.
Using the Arduino for a commercial product is totally unsuitable for a variety of reasons, with the only exception being if it was branded as "Arduino-compatible" or some such, explicitly meant to be modified by the user (but I wouldn't consider that "commercial").
Sourcing Atmel components is ...
Chris disagrees, but I can't envision any practical instance where you would use it
@tyblu, @markrages - Thanks. I didn't design the board, so I don't know why the 741 is being used. Oh well. I didn't find that line about the maximum input voltage in the datasheet, but I pretty much assumed it.
@Nick - I can't either, but the only place I can see it being used is internally. I don't imagine that you'll ever see a product in a retail store that has an Arduino inside it.
I might understand it being used for production support or product verification. It's a poor choice, but it does have a decent dev environment.
Let's assume that the cost of goods is an insignificant factor. If a company lacks a team to produce a custom board for a particular product, but has success with an off-the shelf development platform like Arduino / Netduino / mbed, what sorts of things should be considered before going forward?...
@NickT I can't find it. There are a zillion Arduino hits. Tangentially, there's a good argument for including it in a product: market exposure. eevblog.com/forum/index.php?topic=173.45
Using the Arduino for a commercial product is totally unsuitable for a variety of reasons, with the only exception being if it was branded as "Arduino-compatible" or some such, explicitly meant to be modified by the user (but I wouldn't consider that "commercial").
Sourcing Atmel components is ...
