I have two built circuits and I am trying to integrate them. In one ciruit there is 74HC14 IC and there is a 2.2k resister between two gates (pin2 and pin 3) and in other circuit they are directly connected (pin1 and 2). I want to know why is 2.2k resister used? I know the purpose is to invert the output of first gate but why we can't directly connect those pins in both cases?
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Good day everyone.! Anyone can help me on my project? ''Eye detection sensor: a developmental research on alert system for drivers fatigue.'' my plan is to use a camera to m0nitor the m0vement of the iris but i d0nt knw how will i start., please i really need it...
Sorry for the mistake. I wanted to say pin2 and pin3. The two circuits are x10 transmitter and a x10 receiver. 74HC14 is used to detect the zero crossings of the AC power lines. (x10 is a protocol that is used to communicate over power lines) And I want to combine both transmitter and the receiver together and create a transceicver. In the transmitter ciruit pin2 and pin3 of 74HC14 is directly connected and in the receiver circuit they are connected through a 2.2k resister. I want know the difference inbetween so that I can use either directly connection or the connection through 2.2k resister for my combined transceicver circuit.
The only possible reason for using the resistor is to introduce a tiny delay in the signal but it would be so insignificant at power line frequency as to be useless. In some designs a resistor is used to isolate a driving signal from the pin it drives so test signals can be injected or the logic gate can be tested in-circuit.
Your schematic seems to be missing a pull-up resistor on pin 1 and a ground on the opto-couplers. Wouldn't it be a better and cheaper solution to use a bridge rectifier and one opto?