- Why do TTL integrated circuits assume unconnected inputs to be at logic 1?
- What is fan-in and why is it important in the operation of a logic gate?
- What happens to the gate output of NOT logic gate when its input voltage level reaches from 0.4 V to 2.4 V?
- Is it possible for a gate output to receive current from other sources? If so, what amount of current can it receive?
EDIT: Here are my final answers.
- TTL integrated circuits assume unconnected inputs to be at logic 1 because the main requirement for driving a TTL input is to pull-down the level to near 0 V which takes about 1 mA per input.
- Fan-in is the number of physical inputs on a gate. For example, if you need a 2-input AND gate and you have only one input, you need to add logic. [Thanks for the example, @SpehroPefhany. I need to use AND since we haven't discussed NAND yet.]
- There would be no certain response because it is within the noise margin. No logic gate manufacturer would guarantee how their gate circuit would interpret such signal.
- Yes, it could come from the voltage source and the ground. If the output terminal is connected to the form,er it is called sourcing current; to the latter, switching current.