[ARC5] No Doubt Dumb Tube Question

[WA5CAB at cs.com]

I did not take the time to go and look up the 5AR4 but although the 
standard tube basing diagram is drawn showing a separate heater and cathode, the 
latter is shown as being internally connected to pin 8 along with one side of 
the heater.  So in the practical (electrical) sense it is directly heated 
just like the 5R4.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 06/17/2013 12:56:26 PM Central Daylight Time, 
jwiley at gci.net writes: 
> Well, two 5-volt heater indirectly heated rectifiers come to mind 
> immediately, the 5V4 and the GZ34 / 5AR4. There may be others.
> 
> - Jim, KL7CC
>