I agree, comparators would have been better. I built this h-bridge for a school project and I only had a week to do it, so I was limited to whatever the lab tech had in stock. (which is also why I used a NAND gate for U6 instead of an inverter.)

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Jeff
To the optimist, the glass is half full.
To the pessimist, the glass is half empty.
To the engineer, the glass is twice as big as it needs to be.