De buisjes uit zijn scopes zijn kleine spannigstablisatoren en hebben maar twee draadjes. Philips heeft ze de prefix ZZxxxx gegeven.
De gele stip is waarschijnlijk de bijbehorende type codering. Het nummer staat alleen op het doosje.
rode stip: ZA1002
kleine gele stip: ZA1003
grote gele stip: ZA1004
blauwe stip: ZA1005
Hier wat Ronald Dekker er over schrijft:
The ZA1000 and ZA1002 are switching “diodes”, the ZA1001 is a relaxation diodes suitable for timing circuits, while the ZA1003 and ZA1004 are indicator tubes suitable as read-out diodes for transistor circuits [3.p227]. The statistical breakdown of the tubes is reduced to less than 1 msec for a 10-20V overvoltage by the inclusion of a small quantity of tritium. The delay, however, is not reduced sufficiently for timing circuits where the tube acts as a relaxation oscillator at relatively low frequencies, and where it is essential for the tube to strike at the same voltage on each pulse. There is no problem at higher frequencies, since the tube does not have sufficient time to de-ionize completely between pulses, and there is sufficient residual charge to bridge the gap. To overcome the low-frequency problem the tube designed for timing circuits, the ZA1001, has a small quantity of heavy gas (Kr or Xe), which has a long de-ionization time, added to the main gas. So by combining a fast and slow de-ionization process in one discharge, the tube is able to oscillate over a comparatively wide frequency range.