โก High and Low
In digital systems, signals are often described as High or Low.
๐ Electrical Voltage Levels
At their core, High and Low refer to voltage regions
| Term | Electrical Meaning | Typical Voltage Range (5V logic) |
|---|---|---|
| High | Elevated voltage (near Vcc) | ~2V to 5V |
| Low | Grounded voltage (near GND) | ~0V to 0.8V |
These are physical descriptors:
- High means the signal line is carrying a voltage close to the positive supply rail.
- Low means the signal line is close to ground.
They do not inherently mean 1 or 0โthose meanings are assigned by context.
๐บ๏ธ Mapping Voltage to Logic
To interpret High/Low as binary values, we need to know the signalโs polarity:
| Signal Type | High Voltage Meansโฆ | Low Voltage Meansโฆ |
|---|---|---|
| Active-High | Asserted / TRUE / 1 | Deasserted / FALSE / 0 |
| Active-Low | Deasserted / FALSE / 0 | Asserted / TRUE / 1 |
So:
- High voltage always means elevated potential
- But whether that means
1or0depends on whether the signal is active-high or active-low
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