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Old 4th Dec 2019, 3:46 pm   #6
Sideband
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Join Date: Oct 2003
Location: Croydon, Surrey, UK.
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Default Re: Grundig 7070W hot resistor.

If you want to be sure that there are no problems with excessive HT current, why not measure it? It may not be given in the circuit but you can work out roughly what it should be by looking at the valve data. I doubt that the rest of the valves plus the screen grid of the output valve amounts to more than around 40mA so the resistor should be running at just under 2 watts. Ohms law for power (I sqrd R) so (0.04A <squared> x 1200 ohms) = 1.92 watts.....just a rough idea. Alternatively, measure the voltage across the resistor, square it and divide it by the resistance (P=E squared / R)
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