One semi.

 

Wow. I didn't realize I created a competition. Laugh Out Loud.
Thanks. I will attempt circuit 2 first.

 

First pass at an alternate solution.

The ULN2003 has seven individual small power darlington transistors, with a common ground and a transient protection diode on each output. Each one is rated for 50 V and 0.5 A. It makes a great logic device for rugged environments, with each section acting as a high voltage open collector inverter. The small schematic in the corner shows the internal connections of each section. Two sections back-to-back form a flipflop, and five sections in parallel form the output motor driver. One chip, 2 resistors, no capacitors.

ak
View attachment 114713

I think it should be ULN2004...

 

I think it should be ULN2004...

While the input of the 2004 is rated for 6 to 15 V, that assumes a direct-drive circuit. A passive pull up resistor acts with the 2004 input circuit to form a voltage divider. This limits the available drive current, making it difficult to get firm darlington semi-saturation for the lowest internal heat generation. The 2003 works much better in this application, especially when one pullup resistor has to "drive" multiple sections. With the 2004, the pull up resistor has to be such a low value that it unnecessarily increases the power dissipation in the driving stage when it is pulled low.

ak

 

While the input of the 2004 is rated for 6 to 15 V, that assumes a direct-drive circuit. A passive pull up resistor acts with the 2004 input circuit to form a voltage divider. This limits the available drive current, making it difficult to get firm darlington semi-saturation for the lowest internal heat generation. The 2003 works much better in this application, especially when one resistor has to "drive" multiple sections. With the 2004, the pull up resistor has to be such a low value that it unnecessarily increases the power dissipation in the driving stage when it is pulled low.

ak

Thanks AK...

 

Any time.

 

unl2003 it is and 2 resistors it is then

 

Does terminal 8 go to ground?
Do i attach anything to terminal 9?

 

Does terminal 8 go to ground?
Do i attach anything to terminal 9?

That's shown in the bottom right of AK's post #17.

 

That's shown in the bottom right of AK's post #17.

I thought so. Just wanted to confirm. Thank you

 

Does this look correct? Iif so I will start building it
Thanks

 

Note that the seven sections are completely interchangeable. You can swap sections 1 and 2 for sections 7 and 6. This brings the input connectors closer to the chip ground pin, and the two pullup resistors closer to the chip COM (+12V) pin.

ak

 

Note that the seven sections are completely interchangeable. You can swap sections 1 and 2 for sections 7 and 6. This brings the input connectors closer to the chip ground pin, and the two pullup resistors closer to the chip COM (+12V) pin.

ak

Ok. Thanks