electrical (ece) Curriculum

In this experiment, we were tasked with building and testing an analog timer circuit in two distinct parts. The first part involved constructing an RC circuit, where a capacitor charges when a jumper is unplugged, and ensuring the capacitor charges from 0 to 5V as expected. To build this part of the circuit, we used a jumper wire in place of a switch and observed the capacitor’s charging behavior. The second part of the circuit involved the use of an IRF510 metal-oxide-semiconductor field-effect transistor (MOSFET), which controlled a light-emitting-diode (LED). The MOSFET acts like a switch, allowing current to flow through the LED once the voltage across the capacitor reaches a threshold, turning the LED on. After verifying the functionality of both sections separately, we connected them so that the LED would light up approximately one second after the jumper was unplugged, as the capacitor charges and triggers the MOSFET. We then integrated an oscilloscope using the Analog Discovery 2 (AD2) to monitor the capacitor’s charging process and the current through the LED, adjusting the time base and settings to capture both events clearly. We also added a math channel in the Waveforms application to calculate the current flowing through the LED by measuring the voltage across a 470Ω resistor in series with it. To further analyze the circuit, we replaced the 4.7kΩ resistor with two other values, calculated the expected time constants, and measured how long it took for the LED to turn on with each resistor.