Difference between AT and ATX Power supply

AT and ATX stand for Advanced Technology power supply and Advanced Technology Extended power supply. Both are types of Switch Mode Power Supply (SMPS). Switch mode power supply provides electrical power to an electrical load. SMPS uses a switching regulator for efficient conversion of electrical power.

Difference between AT power supply and ATX power supply:

S. No.	Category	At power supply	AtX power supply
1.	Full Form	AT power supply stands for Advanced Technology power supply.	ATX power supply stands for Advanced Technology Extended power supply.
2.	Motherboard Required	It can be supplied to AT motherboard	It can be supplied to ATX motherboard
3.	Number of power connectors	The main power connectors in AT power supply are 2 in number.	There is only 1 main power connector in ATX power supply.
4.	Number of pins per connector	There are 6 pins per connector in AT power supply.	There are 20 or 24 pins per connector in ATX power supply.
5.	Number of rows on pins	The pins in AT power supply are arranged in a single row.	The pins in ATX power supply are arranged in 2 rows.
6.	Switching the power on/off	It has a physical switch which can be operated manually.	It has a switch which can be operated by a software by the motherboard.
7.	Power Supply	Power provided by AT power supply is less than 250 Watts.	Power provided by ATX power supply is more than 300 Watts
8.	Unique Connectors	It has mini-Molex connectors for floppy devices.	It has a SATA (Serial Advanced Technology Attachment) connector.
9.	Manufactured by	It was manufactured by IBM.	It was manufactured by Intel.
10.	Year of Manufacture	It was manufactured in 1984.	It was manufactured 1995.