In this experiment, you return to the circuit "The Transistor as a Switch" from the experiment 7. You weaken the signal to the base further.
In order to archive this, replace the resistor R1 with a resistor of 1MW.
Now you need to turn the potentiometer much further before the LED lights up. Also, it takes longer until the transistor is saturated and the LED lights up brightly. The signal is much weaker.
In a next step make sure the signal at the base is very weak. Turn the potentiometer until the LED lights barely perceptible.
Now leave the circuit unaltered and go to the next experiment.