I recently acquired a bunch of vacuum tubes from ebay and I'm in the process of trying to design a simple tester to check the functionality.
Below is what I'm currently thinking about:
I managed to scrape a transformer that was used to output 6V from various input voltages; so I'm inputting 6VAC to get different HVs on the secondary (from 110 to 240VAC).
This would connect to a full bridge rectifier filter capacitor (the switch to the rectifier tube to be tested is an impromptu idea that I got right now). The rectified voltage then goes through a potentiometer to get 200V (on the picture 220 is wrong), 0V (ground) and -20V for the polarization. The rails that come out of the first potentiometer go through other another potentiometer to set the variable voltages (0 - -20V and 0 - 200V). This latter rails will go to pins to be connected to the D.U.T..
I used the voltage dividers because I would like to have at the same time 200V to have a decent plate voltage, a variable bias voltage for the control grid and a variable voltage for the control grid.
I know that the voltage dividers are not exactly the best option but I would like to keep it as simple as possible and is not essential that the device is power efficient. Would this be a feasible idea?