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.
Pin Description:
| Pin No | Function | Name |
| 1 | Ground (0V) | Ground |
| 2 | Input voltage (5V-18V) | Input |
| 3 | Regulated output; 5V (4.8V-5.2V) | Output |
