... sensors.3.2.1 InputsIn smaller PLCs the inputs are normally built in and are specified when purchasing the PLC. For larger PLCs the inputs are purchased as modules, or cards, with 8 or 16 inputs of ... and appear to be working with a diminished voltage. If DC is connected to an AC triac output it will turn on and appear to work, but you will not be able to turn it off without turning off the ... until the current stops flowing. This is fine with AC current because the current stops and reverses every 1/2 cycle, but this does not hap-pen with DC current, and so the triac will remain...