The **74LS04** is a member of the 74XX series of TTL (Transistor-Transistor Logic) integrated circuits. It is specifically a **Hex Inverter**, meaning it contains six independent NOT gates in a single package. --- ### 1. Key Technical Specifications The "LS" in the part number stands for **Low-power Schottky**, which balances high-speed switching with lower power consumption compared to the original 7404 series. | Parameter | Typical Value | | :--- | :--- | | **Logic Family** | TTL (Low-power Schottky) | | **Operating Voltage (Vcc)** | 4.75V to 5.25V (Standard 5V) | | **Number of Gates** | 6 (Hex) | | **Output Type** | Push-Pull | | **Propagation Delay** | ~10ns to 15ns | | **Operating Temperature** | 0°C to 70°C | --- ### 2. Pin Configuration The 74LS04 is usually housed in a 14-pin DIP (Dual In-line Package). | Pin Number | Function | Description | | :--- | :--- | :--- | | **7** | **GND** | Ground (0V) | | **14** | **Vcc** | Power Supply (+5V) | | **1, 3, 5, 9, 11, 13** | **Inputs** | Logic Inputs (A1 to A6) | | **2, 4, 6, 8, 10, 12** | **Outputs** | Inverted Logic Outputs (Y1 to Y6) | --- ### 3. Logic Function (NOT Gate) The fundamental operation of each gate in the 74LS04 is to output the opposite logic state of the input. **Truth Table:** | Input (A) | Output (Y) | | :---: | :---: | | Low (0) | High (1) | | High (1) | Low (0) | **Boolean Equation:** `Y = NOT A` (or $Y = \bar{A}$) --- ### 4. Common Applications * **Logic Level Shifting:** Converting signals between different logic stages. * **Clock Signal Generation:** Creating square waves or oscillators when combined with resistors and capacitors. * **Waveform Squaring:** Sharpening the edges of slow-rising signals into clean digital pulses. * **Buffer/Driver:** Using multiple gates to drive LEDs or other low-power components (though current is limited). --- ### 5. Circuit Symbol In a schematic, the 74LS04 is represented by the standard triangle with an inversion bubble: ```text |\ Input | >o Output |/ ```