7409 QUAD 2- INPUT AND GATE POSITIVE LOGIC
with open-collector outputs
The 7408 IC package contains four independent positive logic AND GATES. Pins 14 and 7 provide power for all four logic gates. The Open-Collector outputs require pull-up resistors for proper logical operation. The OPEN-COLLECTOR outputs can be wired together to produce AND gates with more inputs without the need for additional logic gates.
The circuit on the left shows how the gates of the 7409 can be wired together to act as a larger gate. In the circuit the LED will only glow if all inputs (A,B,C, and D) are high, acting like a 4-input AND gate.
Use caution when wiring chip and be sure to check which pins are outputs and inputs!
AND GATE Logic-Rules:
The output is HIGH when both inputs are HIGH, otherwise output is LOW.