An ADC turns an analog input into a digital code. A flash ADC compares the input against many thresholds in parallel. A successive-approximation ADC tests code bits using an internal DAC and comparator. A counter-type ADC steps a count until its DAC output reaches the input.
Worked example
Consider a three-bit successive-approximation model with a 0–8 V range and a stable 5.3 V input. Test 100, representing 4 V: keep it. Test 110, representing 6 V: clear the added bit. Test 101, representing 5 V: keep it. The final illustrative code is 101.
What to watch for
Real ADCs have specified code-transition conventions, input acquisition limits and conversion timing. This ideal walk-through does not define every device's rounding behavior.
Try it yourself
How many comparators does a basic three-bit flash ADC use?
Answer: 2^3 − 1 = 7 threshold comparators, followed by encoding logic.
How to study this topic
Separate the ideal logical model from the physical device interface. Write units beside capacities, voltages and timing values. The architecture explains the idea; the chosen part's documentation supplies the operating limits.
Explore related programmes
These recorded programmes are upcoming. This article is general educational content, not a syllabus or course sample.
Digital Electronics