Hormonal contraception is highly effective: when taken on the prescribed schedule, users of steroid hormone methods experience pregnancy rates of less than 1% per year. Perfect-use pregnancy rates for most hormonal contraceptives are usually around the 0.3% rate or less.
A programmable logic controller (PLC), or programmable controller is an industrial digital computer which has been ruggedised and adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability control and ease of programming and process fault diagnosis.
Now, one of the old guys! In PLC work NPN means the sensor or switch connects to the negative of the power supply. When the sensor is made up it connects the plc input to the negative and makes up the PLC input point. The PNP is the same except it connects the PLC input to the positive side of the supply. In most of my plc work we use NPN type sensors.