[ARC5] GO-9 Project: Why the Resistor?

[John Hutchins]

David -

Without seeing other post to this question : to limit in rush current on 
the filament.

Hutch


On 10/22/2019 2:28 PM, David Stinson wrote:
>
> Dear Smart People:
> Please take a look at the GO-9 transmitter schematic attached. The 837 
> MO and 837 IA tubes are supplied filament voltage from the same buss.  
> However, the connection to the 837 IA tube goes through R-312, a 4.5 
> Ohm 20 Watt resistor (red arrow).  At the 0.7 Amp current of the 837, 
> this is going to drop around 3 Volts, reducing the tubes filament 
> voltage from 12.6 VAC 800Hz down to 9.6 V.  I haven't found a mention 
> of this in the manual's circuit description.  Why would they do this?
>
> TNX OM ES 73 DE Dave AB5S
>
>
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