7905 is a voltage regulator integrated circuit. It is a member of 79xx series of fixed linear voltage regulator ICs. The voltage source in a circuit may have fluctuations and would not give the fixed voltage output. The voltage regulator IC maintains the output voltage at a constant value. The xx in 78xx indicates the fixed output voltage it is designed to provide. 7905 provides a regulated supply of -5 V and 1A current. Its additional features include internal thermal overload protection, short circuit protection and output transistor safe operating area compensation.
Input voltage (5V-18V)
Regulated output; 5V (4.8V-5.2V)