Lab Report: Simple Electrical Circuit for an LED Lamp 1. Circuit Description and Connection Circuit Path: Positive Terminal of 9V Battery -> 1 k Ohm Resistor -> Anode (+ leg) of LED -> Cathode (- leg) of LED -> Negative Terminal of 9V Battery. 2. Multimeter Readings and Measurements - Battery Voltage (V_total): 9.00 V - LED Voltage Drop (V_LED): 2.10 V - Voltage Across 1 k Ohm Resistor (V_R): 6.90 V - Measured Circuit Current (I): 6.90 mA (0.0069 A) 3. Power Calculation Formula: Power (P) = Voltage (V) x Current (I) Using the measured values for the LED: V_LED = 2.10 V I = 0.0069 A Calculation: P_LED = 2.10 V x 0.0069 A = 0.01449 W (or 14.49 mW) 4. Principles of Energy Conversion and Component Roles Energy Conversion: Chemical energy stored inside the 9V battery is converted into electrical energy, pushing free electrons through the wires. When these electrons pass through the semiconductor material inside the LED, they recombine with electron holes, releasing energy as light photons (light energy) along with a very small amount of heat. Role of the Resistor: An LED has almost no internal resistance once turned on. Without the 1 k Ohm current-limiting resistor, a 9V battery would push excessive current through the LED instantly, causing it to overheat and burn out. The resistor limits current flow to a safe level (under 10 mA), protecting the LED while maintaining a bright light. 5. Strategies for Improving Energy Efficiency 1. Reduce Unnecessary Resistance Loss: In this setup, the 1 k Ohm resistor drops 6.90 V out of 9 V, meaning most of the battery's energy is wasted as heat through the resistor (P = 6.9 V x 0.0069 A = 47.61 mW). Using a lower-voltage power supply closer to the LED's rating (like two AA batteries giving 3.0 V) requires a much smaller resistor, wasting far less energy. Page 1 Lab Report: Simple Electrical Circuit for an LED Lamp 2. Use Pulse Width Modulation (PWM): For larger LED lamps, replacing passive resistors with active LED drivers or PWM circuits regulates power much more efficiently without wasting energy as heat. 3. Minimize Environmental Impact: Replacing disposable 9V alkaline batteries with rechargeable batteries or small solar panels significantly cuts down on hazardous electronic waste and chemical battery disposal. Page 2