U52, OSRAM, BLACK BASE, HAMMERSMITH, WARTIME PRODUCTION, VT-244, 5U4G, 5U4
U52, OSRAM, BLACK BASE, HAMMERSMITH, WARTIME PRODUCTION, VT-244, 5U4G, 5U4
This Osram U52 valve shows excellent bright getter and tests as GOOD using my AVO VCM163 valve tester. The black base is tight to the envelope and has both a white ink cartouche showing GEC manufacture as well as a faded white print ZB2 marking.
Device test data: Ia = 120.0mA range, GOOD A1 70 / A2 73.
We test our rectifiers using a calibrated and standardised AVO VCM163 on the specified range. This VCM gives a qualitative estimation of emission as you can see from the photo, the GOOD range bar runs below the numerical uA/Ig scale with the GOOD range between 51 - 100. The above device test data, shows the max current range specified and a record of the numerical reading within the GOOD range obtained.