Question

Would the PLC need and NPN or PNP input sensor? Briefly state your rationale. PLC IN D4 INTERNAL OPTO- ISOLATOR R2

Answer 1

Explained.....

Answer : O PNP Transistor NPN Transistor : C с. Ic Ic B IB IB IE 1-1 E 'E

Current > when the sensor senses, Current is first applied to the opto comples, which makes the infrared LED emit light that is proportional to the that allows base current to flow. In the figure a the transistor that is used has circuit Symbol similar to that off NPN transistor, where eurrent flows from Collector to Emitter provided the transistor is triggered Bare current. by Base