Electronics · Semiconductor devices / Principles and inquiry
Transistor switch experiment guide
Use a small base current to control the load and distinguish cutoff, active and saturation regions.
How does it work?
Ic = βIb applies only in the active region; the load limits current in saturation.
Key relationship
Ib = max(0,(Vin−0.7)/Rb) · Ic = min(βIb,(Vcc−0.2)/Rc)
Try this investigation
- Use a small base current to control the load and distinguish cutoff, active and saturation regions.
- Run and record each of the three baseline presets.
- Compare the changed variable and its result with the baseline records.
Interpreting your results
What is the collector-emitter voltage when the same circuit saturates?
0.2 V
Assumptions and limitations
Temperature, leakage, dynamic transistor effects and actual LED voltage drops are omitted. Experiment on screen; do not reproduce this with real power supplies, outlets or high voltage.