Actuator
the students usually propose a power voltage follower, or switching the DC voltage over the bulb with a power transistor or MOSFET, both of them using a PWM signal. Notice that the schematic for switching a MOSFET would be the same as in Fig. 4, but instead of a power transistor we use power MOSFET and eliminate the 22Ω resistor between the 2N2222 collector and, in the case, the MOSFET gate.