A Triode

A <a href="https://en.m.wiktionary.org/wiki/thermionic_valve" title="thermionic valve" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">thermionic valve</a> containing an <a href="https://en.m.wiktionary.org/wiki/anode" title="anode" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">anode</a>, a <a href="https://en.m.wiktionary.org/wiki/cathode" title="cathode" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">cathode</a>, and a <a href="https://en.m.wiktionary.org/w/index.php?title=control_grid&action=edit&redlink=1" class="new" title="control grid (page does not exist)" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(221, 51, 51); hyphens: none;">control grid</a>; small <a href="https://en.m.wiktionary.org/wiki/change" title="change" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">changes</a> to the <a href="https://en.m.wiktionary.org/wiki/charge" title="charge" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">charge</a> on the grid <a href="https://en.m.wiktionary.org/wiki/control" title="control" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">control</a> the <a href="https://en.m.wiktionary.org/wiki/flow" title="flow" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">flow</a> from cathode to anode, which makes <a href="https://en.m.wiktionary.org/wiki/amplification" title="amplification" style="background: none rgb(255, 255, 255); margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161); hyphens: none;">amplification</a> possible.