NAND GATE 5V SW_A A SW_B B GND R R GND O O = A . B A = 0 / L / 0V B = 0 / L / 0V O = 1 / H / 5V LED : ON A B A.B O 0 0 0 1 0 1 0 1 1 0 0 1 1 1 1 0 NAND Gate IC * 7400 (TTL) * 4011 (CMOS)