TPC Schematic and Symbols Practice Test 2026 - Free TPC Schematic Questions and Study Guide

The solid-state device in an A/C system that can amplify and switch electrical signals is a transistor. Transistors are semiconductor devices that can control the flow of electricity. They function primarily as switches or amplifiers. When used in amplifying signals, they can take a small input signal and produce a significantly larger output signal, making them essential in various applications, including A/C systems where precise control of electrical signals is necessary.

Transistors work by using a small input voltage or current to control a much larger output voltage or current, making them efficient in managing and processing electrical signals within an A/C unit. This capability to both amplify and switch signals allows for greater control and automation in A/C systems, contributing to improved performance and efficiency.

In contrast, a diode allows current to flow in one direction only, and while it is crucial for rectification and protection in circuits, it does not amplify signals. Capacitors are typically used for storing and releasing electrical energy and smoothing out electrical waveforms, rather than amplifying or switching signals. Resistors are components that limit current flow in a circuit; they do not have the capability to switch or amplify signals.