5U4G, SYLVANIA ,5 RIB ,CHARCOAL ANODE, JAN, VT-244 5U4 3K, 1943 PRODUCTION

5U4G, SYLVANIA, 5 RIB, CHARCOAL ANODE, JAN, VT-244, AIR MINISTRY BASE SLEEVING

This Sylvania tall form ST envelope 5U4G valve shows excellent bright getter and tests as EXCELLENT using my AVO VCM163 valve tester.  The base-envelope junction is encircled by a brown heatshrink sleeve - a palliative measure against envelope separation employed by the Air Ministry during the late 1950s which marks this device as Air Ministry issue.  The black base is tight to the envelope and carries a white ink Sylvania VT-244 legend in addition to the etched octagonal cartouche

Device test data: Ia = 120.0mA range, GOOD  A1 74/ A2 77.

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.