Hi,
I am a little worried about the reverse current through the pushbutton. I am using it to power on an Arduino. When the pushbutton is off and I plug the Arduino in to the USB to program, the green light on the pushbutton comes on, making me worried that it is getting hit with reverse current. It is a pretty basic set up. The Vout of the pushbutton goes to the Vin on the Arduino. Should I use some kind of diode to prevent this? If so, what type?
Thanks!
Tyler
Hello, Tyler.
A schematic of the board is on the product page. You can see that the LED is powered from VOUT, so, if you have sufficient power there, it will turn on. Please note that there is a diode between VOUT and VIN (through the body of the MOSFET), so, if VOUT is high enough above VIN, current can flow that way. That’s not likely to be a problem for the power switch, but if your power source does not like reverse power, or if it draws a lot of current from the USB port, it could be a problem. You can add a diode (one that can handle the current your setup will draw from the power supply), or if you connect to the Arduino’s power jack, you can use the diode already on the board.
- Ryan
Thanks Ryan!
A somewhat unrelated question. What if I have manual switches set up that could frequently close circuits to both the “power on” button and also the “off” terminal simultaneously? I guess I will find out soon enough which will win out, but is there any harm to the pushbutton SV if that occurs?
I don’t expect any trouble if OFF is HIGH when the pushbutton is activated. I think it is likely that the shutdown will win, but I haven’t tested it.
- Ryan
OK, I’ll let you know! 
I’m making a puzzle where the user has to press the correct 4 out of about 8 buttons to activate the device. I want the “wrong” 4 buttons to initiate the shut down, hopefully preventing the puzzle from powering on.
So I’ll wire the 4 correct buttons in serial to the power on. And the 4 wrong buttons in parallel to the off terminal.
