U52, GEC, MILITARY APW4000, BLACK BASE, HAMMERSMITH, WARTIME PRODUCTION, VT-244, 5U4G, 5U4

U52, GEC, MILITARY APW4000, BLACK BASE,  HAMMERSMITH, WARTIME PRODUCTION, VT-244, 5U4G, 5U4

This GEC U52 valve shows excellent bright getter and tests as GOOD using my AVO VCM163 valve tester. The black base is tight to the envelope which shows the phaeon, factory markings for GEC-MOV Hammersmith and the Admiralty Pattern notation APW4000.

Device test data: Ia = 120.0mA range, GOOD  A1 70 / A2 70.

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 maximal value of which varies due to valve type and intrinsic rA.  The above device test data, shows the max current range specified and a record of the numerical reading within the GOOD range obtained.