Digital Electronics
Guess first
Is 2.4 V a logic 1 or a 0?
Most students get this wrong: a 5 V chip reads 2.4 V as what?
Quick check · tap an answer to continue
Lesson notes
Explain how voltages represent 0 and 1 and convert between binary, hex and decimal
Key points
- A TTL input treats anything from about 2 V up to 5 V as HIGH, so 2.4 V is a clean logic 1.
- Voltages between 0.8 V and 2 V are undefined, which is why a bit is a range, not one exact voltage.
Definitions
- Logic level
- A defined voltage range that a gate reads as binary 0 or 1
Takeaway: Logic levels are voltage ranges, not exact voltages.
Quick check: A 5 V TTL gate input sits at 2.4 V. What does the gate read?
- Undefined, not 5 V
- Logic 0
- Logic 1
Logic 1 is any voltage in the HIGH range, not exactly 5 V.
logic levelbitradixLogic levelBit
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