Tube DIY Asylum

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RE:I have a 200ma Fluke or something like that.

Posted by SteveBrown on June 19, 2017 at 07:23:40:
Using a ma meter as a ma meter should be straight forward, but not all ma meters are created equal, some expect you to know to put in a shunt resistor but others have this built in. Use a battery and a resistor, figure out current and put the meter in series, if it reads correctly (you can verify with a digital meter), then fine, just insert it. That being said, I'm always nervous of wires and screw terminals coming lose so I put a shunt to ground, like 100 ohms. The small resistance of the ma meter will swamp that resistor in normal practice, but if the meter connection opens, the output tubes will not red-plate.