LM7805 is one of the most commonly used Positive Regulator in Electronic circuits to lower down the voltage from the higher input voltage and it provides a regulated output of +5V with 2% regulation. This regulator has a ~2.5V linear drop-out. That means it must get at least +7V to get a clean +5V out. It dissipates the excess voltage in the form of heat, so you need to use a heat sink along with it to make sure it is working properly. There is a constant ‘quiescent’ current draw of 6mA. It has 3 terminals in the TO-220 package and it can handle up to 1A current. It is commonly used in Regulated power supply, as a current limiter in certain applications, constant 5V supply in many microcontrollers, sensors, and electronic appliances, etc. If you want a negative -5V Voltage Regulator, check out LM7905 IC.