Step 2: Open Falstad simulation
Step 3: Questions
Inside, they are very similar to diodes. The arrow shows direction of current and differentiates the 3 pins:
- Collector: Primary input – provides current
- Base: Second input – turns on/off
- Emitter: Output
When the base receives a small current, the NPN transistor allows current to flow from the collector to emitter.
1. What happens when the resistor (10k) connected to A is removed?
2. Is A or B the main source of current? (check Falstad)
3. What happens if you flip the direction of the transistor?
4. Why does the base have a 10k resistor, but the emitter and LED have a 220Ω.