This study guide covers key concepts related to circuits, voltage, resistance, current, and multimeter use. Study Lectures 1-4 and Labs 1-2.
Voltage (V): Electric potential difference between two points in a circuit, measured in volts (V) and acts like electrical pressure that pushes electrons through a conductor.
Key Concepts:
Ohm’s Law: V = IR (Voltage = Current × Resistance)
Series Circuits: Voltage is divided among components.
Parallel Circuits: Voltage remains constant across all branches.
Voltage Divider: A series circuit that divides voltage proportionally among resistors.
Key Equations:
Ohm’s Law: V = IR
Resistance (R): Opposes the flow of current in a circuit, measured in ohms (Ω). It depends on the material, length, and cross-sectional area of the conductor.
Key Concepts:
Series Circuits: Total resistance is the sum of all resistors.
Formula: Rtotal = R1 + R2 + ...
Parallel Circuits: Total resistance decreases as more resistors are added.
Formula: 1 / Rtotal = 1 / R1 + 1 / R2 + ...
Thermistors: Resistors whose resistance changes with temperature.
Wire Resistance: Resistance increases with length and decreases with greater diameter.
Key Equations:
Parallel Resistance Formula (for two resistors): Req = (R1 × R2) / (R1 + R2)
Current (I): Flow of electric charge through a circuit, measured in amperes (A). It depends on voltage and resistance according to Ohm’s Law.
Key Concepts:
Series Circuits: Current remains constant throughout.
Parallel Circuits: Total current is the sum of branch currents.
Short Circuits: Dangerous! Occurs when resistance drops very low, causing high current.
Fuses & Circuit Breakers: Protect against excess current by breaking the circuit.
Key Equations:
Ohm’s Law (Rearranged for Current): I = V / R
Power Formula: P = IV
Multimeter: Measures voltage, current, and resistance in circuits.
Key Concepts:
Measuring Voltage: Multimeter must be placed in parallel with the component.
Measuring Current: Multimeter must be placed in series with the circuit.
Measuring Resistance: Remove the component from the circuit before measuring.
Ammeter Mistake: Connecting in parallel creates a short circuit and may damage the multimeter.
Key Equations to Memorize:
V = IR - Ohm’s Law
P = IV - Power Formula
✅ Understand Concepts, Not Just Equations:
Know why voltage drops in series, but remains the same in parallel.
Understand why increasing resistance reduces current (Ohm’s Law).
✅ Practice Real-World Applications:
Use multimeters correctly.
Understand fuses, breakers, and short circuits.
✅ Use TinkerCAD Simulations:
Simulating voltage dividers, LED circuits, and parallel vs. series resistors helps reinforce learning.
✅ Flashcards for Equations & Concepts:
Memorize key equations but focus on how they apply to circuits.