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What Dana posted is called a "tuning eye tube" or "indicator tube." In tuning eye use in radios, the tube worked off the radio AGC/AVC (Automatic Gain Control) voltage which increased more negative on strong stations. Those tubes had a high impedance input similar to modern multimeters, AKA they did not "load" the circuit they were connected into. They were also used on condenser/ capacitor testers. But that could also be something like a neon bulb.

I searched "Stromberg HRL" and came up NADA "High Resistance Load?" No idea