©  Tube Collection Udo Radtke,

Balometer werden zur Feldstärkemessung im Mikrowellenbereich verwendet.

  under construction

Comments from TCA.

Bolometers usually consist of a non-inductive resistor in thermal but not
electrical contact with a thermocouple in a vacuum. The heat transfer is a
true RMS function so RF power may be read directly.

To the best of my recollection, bolometers were used in a bridge circuit, where one would be subjected to RF and of course ambient, and the other to ambient temperature only. This way, at least in theory, the effects of ambient temperature changes would be cancelled out.

I think I know what Bill means by his "true RMS" comment. 

If the reader usually says "Watts RMS" then read on......

The topic happens to be one of my soap-box favs. As there are also quite a few audio guys here [and they do tend to believe in Watts RMS] I'll start the ball rolling.

For simplicity consider a sinewave voltage applied to a resistor. The RMS voltage of a sine wave gives the same heating effect as the same voltage DC.

The power in the resistor is given by V RMS multiplied by I RMS, and that power is the AVERAGE power. It is NOT the RMS power; it is not Watts RMS.

If the letters RMS appear after the W then it is only to indicate that it is 'RMS derived' power.

I invite the skeptics to try a simple graphical analysis. Draw the above voltage and current waveforms on graph paper and calculate the instantaneous powers. Note that the power waveform is a sinusoid. Note that a peak fills a trough/ the area of a peak fills the area of a trough. Note that the result is an area under a straight line.

The resulting power is average power.

Just for fun, perform an rms calculation on the instantaneous values of the power waveform - did you get a non-unity answer ?? That is another reason why one should not write rms after W unless one really does mean it.



Typen / Types:

 Type 4, 7, 2185 von WF,

rot = Röhre + Foto eingebaut /  red = tube in collection + picture on Website
blau = Röhre vorhanden, Foto kommt / blue = tube in collection, picture in progress.
schwarz oder nicht gelistet = fehlt noch /  black or not listed = tube missing in collection.

Type 4 Detail Type 4  

Es handelt sich um die "Leistungsmesslampe OSW2185". 

Der Entwicklungsbericht ist im Industriesalon unter der Signatur 068/0048  eingestellt und stammt vom Oktober 1946.

Type 2185 # 2185 Details  

    Sollte jemand eine Fehler finden oder etwas zu ergänzen haben, so bitte ich um eine Mail. 


   In case there is something incorrect or should be added, please send me a mail.

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