what would happen if u input a signal into an output pin of a chip?
Depends. If the output on the chip is strong, and the source impedance of your signal that you're connecting to the output is high (weak source), then it probably won't hurt the output of the chip. But if the source impedance of your signal is low (like a few ohms), and the driver for the chip output is not very beefy, then you will likely blow the output driver on the chip. Maybe even let a little smoke out of the chip....
the chip could also have output capacitors onboard, or likely, protection diodes across or in series with the output built onto the chip. In this case, the voltage and power rating of the cap, and the current rating of the diodes will determine if they get damaged.
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