Pentode vs Triode connection

[Leevi]

I have tried to find a clear definition for a triode connection
and have noticed that there are many different practices used. What is essential
in triode connection and how it should be done?
/Leevi

[DummyLoad]

tie screen grid (g2) to plate with a 100R resistor. as usually done with pentode configuration, tie suppressor grid (g3) to cathode or ground, whichever you prefer; usually it's easiest to strap g3 to cathode at the socket.

--DL

[HotBluePlates]

I have tried to find a clear definition for a triode connection ...

Screen is tied to the plate, sometimes through a resistor as DL suggested.

When a triode is used, plate current varies with plate voltage. When a pentode's screen is held at a fixed voltage, plate current changes very little with changing plate voltage, and you get characteristic pentode curves.

When a pentode's screen is tied to the plate, the screen voltage varies when plate voltage varies; this causes plate current to vary, so you have the same end result as a triode with the same plate/control grid/cathode geometry as the pentode. This means that different pentodes, when strapped as a triode, will offer differing mu, Gm and internal plate resistance.

Mu from g1 to g2 will be the mu the tube will exhibit when operated in triode mode.

[Leevi]

Thanks for the clarification guys!
Leevi