Water Diya(Deepa)
Components Needed:
Diya (with two holes for metal probes)
2 metal wires (to act as water probes)
3V coin cells (two 1.5V cells in series should work too)
Transistor (2N3904 NPN)
LED
Resistor (220Ω to 330Ω, suitable for LED current limiting)
Small plastic or decorative cup (for aesthetics)
Connecting wires
Connections:
Battery Positive → LED anode.
LED cathode → Transistor collector.
Transistor emitter → Battery negative.
Battery positive → Second probe.
First probe → 1kΩ resistor → Transistor base.
Working Principle:
When you pour water into the diya, the water connects the two probes. This allows a small current to flow through the 1kΩ resistor to the base of the 2N3904 transistor. Once the base current flows, the transistor switches on, allowing current to flow from the collector to the emitter. This completes the LED circuit, causing the LED to glow.