This document discusses building an electric circuit using an op-amp 741 IC chip, 4 LEDs, 4 330 ohm resistors, and 4 10K ohm resistors. The circuit uses the op-amp as a comparator to determine if the battery voltage is greater than the voltage drop across the LEDs, turning the LEDs on. The document instructs how to simulate and test the physical circuit using batteries, a lightbulb, and wires with help from a teacher or carer.