Current through an input resistor A binary-weighted DAC input resistor is 100 kΩ and is tied to a 5 V source. What current flows through this resistor (ideal conditions)?
Electronics
Analog and Digital Converters
Difficulty: Easy
Choose an option
-
A50 µA
-
B5 mA
-
C500 µA
-
D50 mA
Answer
Correct Answer: 50 µA
Explanation
Introduction / Context:Ohm’s law is frequently applied when analyzing DAC input networks to determine branch currents from known resistor values and reference voltages.
Given Data / Assumptions:
- R = 100 kΩ.
- V = 5 V applied across the resistor.
- Ideal components (no leakage paths).
Concept / Approach:Use Ohm’s law: I = V / R.
Step-by-Step Solution:Compute: I = 5 / 100,000 = 0.00005 A.Convert to microamperes: 0.00005 A = 50 µA.
Verification / Alternative check:Check units: volts/ohms = amperes; 5/1e5 = 5e−5 A confirms 50 µA.
Why Other Options Are Wrong:5 mA / 500 µA / 50 mA: off by factors of 100–1000; likely from wrong kilo-to-base conversions.
Common Pitfalls:Misplacing decimal points when converting kΩ to Ω.
Final Answer:50 µA