It was 2nd semester and project submission for Basic Electronics course was due. She and her friends tried a lot to put together a good working piece of electronic shit, but alas! All their efforts were gone to waste. Luckily they found an old circuit, which was to be submitted in the semester before. It was a dark sensor circuit, a circuit which illuminates an LED when light falling on the LDR is blocked.
*LED (Light emitting diode) *LDR (Light dependent resistor)
It was project submission day, they tested the circuit but it wasn’t working. Worried of losing their credits in the course, two of the friends were preparing for the project presentation, while the third one was trying to get it in working state.
The LED lighted up, the two friends couldn’t believe their eyes. Haha! Let me tell you a secret, the third friend exclaimed with joy. The circuit has a loose connection, and when I touch the LED from below, it lights up, it is not lighting up because I blocked the LDR, it is lighting up because it is getting direct supply from the battery.
Listen up, here is what we gonna do, we’ll reach the electronics lab before anyone else from the class does, and give its demo to the teacher. I’ll fool her into thinking that it is a working circuit.
She and her friends reached the lab as fast as they can. She never made a fool out of anyone. Her heart was beating fast, she cannot do it. But her friends depended on her. All sort of thoughts were going on in her brain. What if the teacher found out? It is wrong. I cannot let my friends down.
It’s now or never.
First her friend gave a brief intro of the group mates and the project. Now it was her turn to give demo of how the circuit works. Trying not to laugh when her friend lighted up the LED, she explained how the sensor detects dark.
They got full marks, and the teacher was totally impressed of their efforts.
It was totally fun. She apologized to her teacher in heart, “Sorry, miss S”.
More to read: Dark sensor circuit on breadboard for beginners