NOT gate

This redirect is about NOT in the sense of an electronic logic gate (e.g. CMOS 4049). For NOT in the purely logical sense, see negation, for other uses of similar terms, see NOT. For logic gates generally, see Logic Gate. For other uses, see NOT gate (disambiguation).

INPUT	OUTPUT
A	NOT A
0	1
1	0

The NOT gate is a digital logic gate that behaves according to the truth table to the right. A HIGH output results if the inputs is LOW. If the input is HIGH, a LOW output results. NOT gates are also called inverters.

Symbols

There are two symbols for NOT gates: the 'military' symbol and the 'rectangular' symbol. For more information see Logic Gate Symbols

'Military' NOT Symbol

'Rectangular' NOT Symbol

Hardware Description and Pinout

NOT Gates are basic logic gates, and as such they are recognised in TTL and CMOS ICs. The standard, 4000 series, CMOS IC is the 4049, which includes six independent NOT gates. The pinout diagram is as follows:

Pinout Diagram of a 4049 Hex Inverting Buffer (NOT Gate) DIL-format IC

1 Vdd 2 Output Q1 3 Input A1 4 Output Q2 5 Input A2 6 Output Q3 7 Input A3 8 Vss 9 Input A4 10 Output Q4 11 Input A4 12 Output Q4 13 n.c. 14 Input A6 15 Output Q6 16 n.c.

This device is available from most semiconductor manufacturers such as Philips. It is usually available in both through-hole DIL and SOIC format. Datasheets are readily avaialble in most Datasheet Databases.

Alternatives

If no specific NOT gates are available, one can be made from NAND gates in the configuration shown below. Alternatively, a NOR gate could be used in the same configuration. Any logic gate can be made from a combination of NAND gates or NOR gates.

File:NOT Using NAND.jpg

NOT gate constructed using only a NAND gate