Also, some tubes can be used for stuff they were not designed for - a triode with the grid unconnected (or connected to another element?) can be used as a diode, though I can't wonder why someone would do that. Also, things like Pentodes can be run as triodes (resistor between a couple of the grids).
In Simple terms: Diode = rectifier, used in power supply.
Triode = amplifier, used in gain stages.
-Ed
In Simple terms: Diode = rectifier, used in power supply.
Triode = amplifier, used in gain stages.
-Ed