Ch 2: Resistors Flashcards
Q: What is Ohm’s Law?
A: V = IR, where V is voltage, I is current, and R is resistance.
Q: What is the function of a resistor?
A: To limit the flow of electric current in a circuit.
Q: Define resistance.
A: The opposition to the flow of electric current, measured in ohms (Ω).
Q: What is the difference between resistors in series and parallel?
A: In series, resistances add up; in parallel, the reciprocal of resistances adds.
Q: What is a potentiometer?
A: A variable resistor used to adjust voltage or current in a circuit.
Q: What is a voltage divider?
A: A circuit that divides voltage using resistors in series.
Q: What happens to current in a resistor?
A: Current decreases proportionally to resistance.
Q: How do you read resistor color codes?
A: Each color represents a digit or multiplier; the bands indicate resistance.
Q: What is Thévenin’s theorem?
A: A method to simplify complex circuits into a single voltage source and resistance.
Q: What is the power rating of a resistor?
A: The maximum power a resistor can dissipate without damage.
Q: What is a breadboard?
A: A platform for prototyping circuits without soldering.
Q: What is “resistance tolerance”?
A: The permissible deviation from the nominal resistance value.
Q: Why are resistors used in series circuits?
A: To increase total resistance.
Q: Why are resistors used in parallel circuits?
A: To decrease total resistance.
Q: What is the unit of conductance?
A: Siemens (S), the reciprocal of resistance.
Q: How does temperature affect resistance in a resistor?
A: Most resistors increase resistance with temperature (positive temperature coefficient).
Q: What is a “pull-up resistor”?
A: A resistor used to ensure a known voltage level for a signal line.
Q: Define “droop” in a resistor circuit.
A: Voltage drop due to resistance in the circuit.
Q: What is a current divider?
A: A circuit that splits current using resistors in parallel.
Q: What is the role of a resistor in a low-pass filter?
A: To control the cutoff frequency in conjunction with a capacitor.
Q: How do you calculate total resistance in a series circuit?
A: Add all resistor values together (R_total = R1 + R2 + … + Rn).
Q: How do you calculate total resistance in a parallel circuit?
A: Use the formula 1/R_total = 1/R1 + 1/R2 + … + 1/Rn.
Q: What is the function of a “shunt resistor”?
A: To measure current by providing a low-resistance path.
Q: What is “thermal noise” in resistors?
A: Random noise generated by thermal agitation of charge carriers.
Q: How is a resistor’s value determined?
A: By its material, length, cross-sectional area, and resistivity.
