What should be done to unused inputs on TTL gates?

• They should be left disconnected so as not to produce a load on any of the other circuits and to minimize power loading on the voltage source.
• All unused gates should be connected together and tied to V < sub> through a 1 k Ω resistor. <>
• All unused inputs should be connected to an unused output; this will ensure compatible loading on both the unused inputs and unused outputs.
• Unused AND and NAND inputs should be tied to VCC through a 1 kΩ resistor; unused OR and NOR inputs should be grounded.