Embedded Guru

voltage: force responsible for movement of electrons(electric current) through a electric circuit current:amount of electrons flowing at a point per second

Suppose in a microcontroller ,you have configured the GPIO functionality of a particular pin to input, and if you read the state of the pin when nothing is connected to it,will it be high(Vcc) or low(Gnd).This is difficult to tell and the state it is present is known as floating state(high impedance state).To prevent this unknown state or floating state,a pull-up or pull-down resistor will ensure that the pin is either in a high state or low state.            A pull-up resistor is connected to 3.3V or 5V (Vcc) and the pull-down resisitor is connected to ground(GND).       Pull-ups are often used with buttons and switches. When the pull-up resistor is connected,the input pin will read a high state when the button is not pressed,a small amount of current will be flowing between the input pin and the VCC thus the input pin is reading to close to VCC.When the button is pressed it connects the input pin directly to the ground,the current flows through the resistor to the ground

Phase :  For phase to measure we require two signals, and it gives the time relationships of the signals. Polarity :  Can be measured on a single signal. It refers to positive and negative values of a signal.So a signal can have either positive polarity or negative polarity. Inverting the polarity means shifting the amplitude,so that positive components become negative and negative components become positive. Sine wave are the waves which alternates from positive to negative and back to positivie,place where the voltage is zero volts is taken to be zero degrees and place where the voltage starts becoming negative is taken to be 180 degrees,when it gets back to positive again it is 360 degrees which is 0 degrees. Phase Difference :  Difference between two sinusoidal signals of the same frequency in time or degrees and  they are referenced at the same point is known as phase difference. In-Phase:  Two sinusoidal signals having the same frequency and no phase differenc