Another student wants to control a DC motor from the mbed and therefore builds the circuit of Fig. 3.17B), where VS is a DC supply of appropriate value. As a further indication that the motor is...

Another student wants to control a DC motor from the mbed and therefore builds the

circuit of Fig. 3.17B), where VS is a DC supply of appropriate value. As a further indication that the motor is running, she connects a standard LED, as seen in Fig. 3.3,

directly to the port bit. She then complains of unreliable circuit behavior. Explain any

necessary changes that should be made to the circuit.