Which component would you likely find in a DC motor speed control circuit?

In a DC motor speed control circuit, an operational amplifier (op-amp) is often utilized to process signals from various sensors or to create a control feedback loop. An op-amp can amplify the control signals that dictate the speed of the motor by responding to the voltage levels and adjusting the output accordingly. This enables fine-tuning of the motor's speed based on adjustments to the input signals, ensuring more precise control over the operation of the motor.

While other components such as resistors, relays, and diodes play essential roles in various circuits, they do not typically serve the same function as op-amps in a speed control context. Resistors can limit current but do not actively control speed. Relays can switch the motor on and off but do not provide variable control for speed adjustments. Diodes serve to protect the circuit from back EMF generated by the motor but do not regulate speed on their own. Thus, the use of an op-amp is crucial for effective speed regulation in DC motor control circuits.