Demonstration Triode

Demonstration triodes typically operate with plate voltages between 50-300V. Ensure all high-voltage connections are insulated and inaccessible to students. Never touch internal components while power is applied. Allow the filament to cool for several minutes after use before handling.

The glass envelope is evacuated and under significant pressure differential. Handle carefully to avoid implosion. Do not strike or drop the tube. Keep away from table edges.

Purpose

A demonstration triode with phosphor-coated plate makes electron flow visible. Students observe thermionic emission from the heated filament and see how grid voltage controls current to the plate, illustrating the basis of electronic amplification.

Demonstration triode: large glass vacuum tube mounted vertically on a black base with control knobs for filament, plate, and grid voltages

Figure 1:

Danger: High Voltage Warning

Warning: Vacuum Tube Fragility

Purpose

Safety Warnings

Danger: High Voltage Warning

Warning: Vacuum Tube Fragility

Purpose