Volts and amperage together basically combined in a formula to determine the number of watts, but they are not specifically related to each other. As per Ohm's law V=IR where V is voltage, I is current and R is resistance. since Voltages is equal to current times resistance than makes them directly proportional to each other and therefor related.
Cervical Position. During menstrual bleeding, the cervix is normally low and hard and slightly open to allow the blood to flow out. It feels like the tip of your nose. After your period stops, the cervix remains low and hard and the opening to the uterus (uterine os) remains closed.
Egg white cervical mucus. Once you notice that your CM has the consistency of raw egg whites, you know you're in your fertile period. If you hold it between two fingers, it can stretch an inch or two without breaking in the middle. This type of CM allows the sperm to swim easily into the cervix.