The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC. 74LS05 Hex Inverter (Open Collector) contains six independent inverters. To perform correctly, the open-collector outputs require pullup resistors. These devices may be connected to other open-collector outputs to implement active-low wired-or active-high wire-AND functions. Open-collector devices often are used to generate high VOHlevels

74LS05 Features
- Six Independent INVERT Gates
- Open Collector Outputs Require Pull-Up Resistors
- Also Available in SMD Type
- Operating Temperature to 70°C
- Standard TTL Switching Voltages
74LS05 Specifications
| Supply Voltage | 4.75 – 5.25Vdc |
| Maximum Clock Frequency | 40Mhz |
| Power Dissipation | 2mW/gate @100kHz |
| Minimum Output Current | 8mA |
| Propagation Delay | 10nS |
| Fan Out (TTL Loads) | 20 |
74LS05 Pinout Diagram

74LS05 Pin Description
| Pin No | Pin Name | Description |
| 1 | A1 | Inverter Gate 1 Input |
| 2 | B1 | Inverter Gate 1 Output |
| 3 | A2 | Inverter Gate 2 Input |
| 4 | B2 | Inverter Gate 2 Output |
| 5 | A3 | Inverter Gate 3 Input |
| 6 | B3 | Inverter Gate 3 Output |
| 7 | GND | Ground |
| 8 | B4 | Inverter Gate 4 Output |
| 9 | A4 | Inverter Gate 4 Input |
| 10 | B5 | Inverter Gate 5 Output |
| 11 | A5 | Inverter Gate 5 Input |
| 12 | B6 | Inverter Gate 6 Output |
| 13 | A6 | Inverter Gate 6 Input |
| 14 | VCC | Positive Supply |
74LS05 Circuit
Here is one simple circuit of 74ls05 with one resistor and LED at the output of a NOT gate.

Applications
- Adjustable-speed ac motor drives.
- Uninterrupted power supplies (UPS)
- Running appliances of ac used in an automobile battery.
74LS05 Alternative Equivalent
74LS04, 74LS06, 74LS07, 74LS14
Download 74LS05 Hex Inverter (Open Collector) Datasheet from the link given below.




