[ARC5] 6K8 or 12K8?

[Leslie Smith]

Dear list,
Recently I put a valve marked as KEN-RAD 12K8 in series with a 12SJ7 (or
VT13x equivalent) and measured the voltage at the junction of the
heaters at 20 volts.  The "mystery" xK8 heater was on the "hot" side of
the 24V supply.

The question:  Did I have a faulty 12K8 or a 6K8 labelled as a 12K8?

Robert Downs suggested a test to answer the Q.  Connect the heater to a
6V supply and measure the current drawn.

Observation:  At 6 volts the "suspect" toob draws 300mA.
Second observation:  A second "toob" marked 12K8 drew 150mA, the correct
value according to the datasheet.

I guess that observation answers the original question.
An errant 6K8 jumped into the 12K8 bin before the labelling machine.


Les



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  Leslie Smith
  vk2bcu at operamail.com

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