Understanding D3 Component
Thought for 54 sec
Here’s a summary of what D3 does in your circuit:
Table
| Property | Details |
|---|---|
| Component | D3 (LED THT) |
| Function | Visual “alarm” indicator driven by U3’s output |
| Anode Connection | Net 11 (NE555 U3’s OUT) |
| Cathode Connection | GND |
| Forward Voltage (Vf) | 1.70 V |
| Series Resistance | 0.42 Ω (internal model) |
| Saturation Current | 93.2 pA |
Explanation:
- [D3] is a through-hole LED used to show when the second 555 timer (U3) goes high.
- When U3’s OUT pin drives Net 11 high (≈9 V), current flows through D3 to GND, causing it to light.
- Its forward voltage (~1.7 V) and small internal series resistance determine its brightness at the available supply voltage.
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