[ARC5] 3A5 Filament Voltage Question

[J. Forster]

Not at all. I can set the PS voltage to anything, and current limit it
anywhere.

I'm trying to find out the minimum operating filament voltage, to allow as
much headroom as possible so as not to accidentally blow the filament.

-John

=============

>> The filament on the 3A5 is parallel wired.
>>
>> The spec sheet says 1.4 VDC, Max. A current alkaline battery will put
>> out
>> significantly more than that.
>>
>> I want to run the thing off an adjustable DC supply, and allow some
>> margin.
>>
>> Does anyone know roughly what the minimum DC filament voltage to apply
>> for
>> enough emission to work reasonably well? I just want to test the
>> operating
>> frequency and get a rough idea of the modulation deviation.
>>
>> Thanks,
>>
>> -John
>
> Is your problem how to obtain 1.2 - 1.4 VDC from a power supply?
> What about two 1N4007's in series, fed from a dropping resistor?
> About 1.2 - 1.3 volts will appear across them, and this voltage will
> remain constant, much like a zener diode circuit.
>
> Sorry if I've misinterpreted your question. I found it difficult to see
> what you're driving at.
>
> 73 de Neil ZL1ANM
>
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