A semiconductor that controls the flow of electricity in a circuit. Usually made of germanium or silicon. This electrical device can amplify a signal.

A semiconductor that controls the flow of electricity in a circuit. Usually made of germanium or silicon. This electrical device can amplify a signal.

• A. Diode
• B. Transistor
• C. Capacitor
• D. Resistor

Answer: (B)

A transistor is a semiconductor device that controls current flow and can amplify signals. It’s typically made from germanium or silicon, with silicon being most common today. In a transistor, a small signal at the control terminal (base for a bipolar transistor or gate for a field-effect transistor) modulates a much larger current between the other two terminals (collector and emitter, or source and drain). That ability to use a small input to regulate a larger output is what enables amplification. By contrast, a diode conducts in only one direction and isn’t used for amplification; a capacitor stores charge and shapes signals; a resistor simply limits current without providing gain.

A transistor is a semiconductor device that controls current flow and can amplify signals. It’s typically made from germanium or silicon, with silicon being most common today. In a transistor, a small signal at the control terminal (base for a bipolar transistor or gate for a field-effect transistor) modulates a much larger current between the other two terminals (collector and emitter, or source and drain). That ability to use a small input to regulate a larger output is what enables amplification. By contrast, a diode conducts in only one direction and isn’t used for amplification; a capacitor stores charge and shapes signals; a resistor simply limits current without providing gain.