Max voltage output avail.on OUT1 - OUT7

[pbronson]

I am interested in what the output voltage is on OUT1 - 7. Is it enough to drive a 12VDC 5.4 Watt solenoid?

Thanks,
Pete

[pbronson]

Sorry, this is on a Prop-1 Controller.

Pete

[JonnyMac]

There is no output voltage on OUT0 - OUT7; those terminals switch ground.  You will connect the other side of your solenoid to the V+ terminal that will carry whatever voltage you plug into the board.

Note: 5.4 watts at 12 volts means the solenoid requires 0.45 amps -- that's a lot of current.  You can run it, but only two at a time.  If you look at the chart below (focus on the yellow dots), you'll see that the max number of outputs when running that much current is two.  If you run more than two of those solenoids simultaneously, the ULN will overheat and blow -- so don't.

[pbronson]

Thanks for the quick reply. I knew about the V+ but didn't explain myself well. As far as input voltage, I saw on a Parallax Board of Education, that a wall wart could be used but only with a max V. of 9VDC while the Prop -1 can handle up to 30VDC. What makes the difference?

Pete

[JonnyMac]

It's just a label -- both devices use the LM2940 regulator that works fine up to 30 volts.  The BoE is frequently used as a small robotics platform and if you feed more than 9v to servos they will go up in smoke.

[pbronson]

Thanks Jon - you are very helpful and make learning this stuff so much easier.

Regards,
Pete