The Basic lessons · Circuit components · B-004-005

Vacuum Tubes and the Triode: History and Function

This lesson explains how vacuum tubes like the triode work, why they were once preferred for high power, and how they compare to modern transistors. You will learn the names and roles of the three internal electrodes that control electron flow.

This lesson is part of SignalPrep Pro. The subsection's 9 exam questions are free to practise: practise B-004-005.

What this subsection asks

• What is one reason a triode vacuum tube might be used instead of a transistor in a circuit?
• Which two elements of a triode carry the output current?
• A feature common to triode tubes and transistors is that both:
• Which electrode on a vacuum tube is operated with the highest positive voltage?
• Which semiconductor device has characteristics most similar to a triode vacuum tube?
• Which electrode of a vacuum triode is the control element?
• In a vacuum tube, which electrode emits electrons?
• What is inside the envelope of a triode tube?
• What term describes a vacuum tube with a cathode, a single grid and a plate?