Let's Make Robots!

Oh, where did I go wrong? - Circuit Quiz (Mystery Solved!)

I built this circuit:
a TTL input on s0 is supposed to turn on Motor 1, and a TTL input on s1 is supposed to turn on Motor 2.
Why the heck does both motors go on when either S0 or S1 go to 5V?

It never ends to amuse me how many ways I can goof stuff up...



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That sounds incredible..

Lame question, I know, but: are you sure everything is connected correctly?

My only other theory is that when one of the motors start, the 12 volt dips slightly because of the large power consumption. This could cause the other circuit to trigger.

What kind of power source are you using? maybe the it cant deliver enough Amps. Since the only wire between the two circuits is the 12V, that seems to be the problem, somehow.

/ vzz-clck-"Maneuver"